LIDAR and rem localization

ABSTRACT

A navigation system for a host vehicle may include a processor programmed to: receive, from an entity remotely located relative to the host vehicle, a sparse map associated with at least one road segment to be traversed by the host vehicle; receive point cloud information from a LIDAR system onboard the host vehicle, the point cloud information being representative of distances to various objects in an environment of the host vehicle; compare the received point cloud information with at least one of the plurality of mapped navigational landmarks in the sparse map to provide a LIDAR-based localization of the host vehicle relative to at least one target trajectory; determine an navigational action for the host vehicle based on the LIDAR-based localization of the host vehicle relative to the at least one target trajectory; and cause the at least one navigational action to be taken by the host vehicle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/US2020/067753, filed Dec. 31, 2020, which claims the benefit ofpriority of U.S. Provisional Application No. 62/957,000, filed on Jan.3, 2020; and U.S. Provisional Application No. 63/082,619, filed on Sep.24, 2020. The foregoing applications are incorporated herein byreference in their entirety.

BACKGROUND Technical Field

The present disclosure relates generally to autonomous vehiclenavigation.

Background Information

As technology continues to advance, the goal of a fully autonomousvehicle that is capable of navigating on roadways is on the horizon.Autonomous vehicles may need to take into account a variety of factorsand make appropriate decisions based on those factors to safely andaccurately reach an intended destination. For example, an autonomousvehicle may need to process and interpret visual information (e.g.,information captured from a camera) and may also use informationobtained from other sources (e.g., from a GPS unit, a speed sensor, anaccelerometer, a suspension sensor, etc.). At the same time, in order tonavigate to a destination, an autonomous vehicle may also need toidentify its location within a particular roadway (e.g., a specific lanewithin a multi-lane road), navigate alongside other vehicles, avoidobstacles and pedestrians, observe traffic signals and signs, and travelfrom one road to another road at appropriate intersections orinterchanges. Harnessing and interpreting vast volumes of informationcollected by an autonomous vehicle as the vehicle travels to itsdestination poses a multitude of design challenges. The sheer quantityof data (e.g., captured image data, map data, GPS data, sensor data,etc.) that an autonomous vehicle may need to analyze, access, and/orstore poses challenges that can in fact limit or even adversely affectautonomous navigation. Furthermore, if an autonomous vehicle relies ontraditional mapping technology to navigate, the sheer volume of dataneeded to store and update the map poses daunting challenges.

SUMMARY

Embodiments consistent with the present disclosure provide systems andmethods for autonomous vehicle navigation. The disclosed embodiments mayuse cameras to provide autonomous vehicle navigation features. Forexample, consistent with the disclosed embodiments, the disclosedsystems may include one, two, or more cameras that monitor theenvironment of a vehicle. The disclosed systems may provide anavigational response based on, for example, an analysis of imagescaptured by one or more of the cameras.

In an embodiment, a navigation system for a host vehicle including atleast one processor programmed to determine at least one indicator ofego motion of the host vehicle. The at least one processor may also beprogrammed to receive, from a LIDAR system associated with the hostvehicle and based on a first LIDAR scan of a field of view of the LIDARsystem, a first point cloud including a first representation of at leasta portion of an object. The at least one processor may further beprogrammed to receive, from a LIDAR system associated with the hostvehicle and based on a first LIDAR scan of a field of view of the LIDARsystem, a first point cloud including a first representation of at leasta portion of an object. The at least one processor may also beprogrammed to receive, from the LIDAR system and based on a second LIDARscan of the field of view of the LIDAR system, a second point cloudincluding a second representation of the at least a portion of theobject. The at least one processor may further be programmed todetermine a velocity of the object based on the at least one indicatorof ego motion of the host vehicle, and based on a comparison of thefirst point cloud, including the first representation of the at least aportion of the object, and the second point cloud, including the secondrepresentation of the at least a portion of the object.

In an embodiment, a method for detecting an object in an environment ofa host vehicle may include determining at least one indicator of egomotion of the host vehicle. The method may also include receiving, froma LIDAR system associated with the host vehicle and based on a firstLIDAR scan of a field of view of the LIDAR system, a first point cloudincluding a first representation of at least a portion of an object. Themethod may further include receiving, from the LIDAR system and based ona second LIDAR scan of the field of view of the LIDAR system, a secondpoint cloud including a second representation of the at least a portionof the object. The method may also include determining a velocity of theobject based on the at least one indicator of ego motion of the hostvehicle, and based on a comparison of the first point cloud, includingthe first representation of the at least a portion of the object, andthe second point cloud, including the second representation of the atleast a portion of the object.

In an embodiment, a navigation system for a host vehicle may include atleast one processor programmed to receive, from an entity remotelylocated relative to a vehicle, a sparse map associated with at least oneroad segment to be traversed by the vehicle. The sparse map may includea plurality of mapped navigational landmarks and at least one targettrajectory. Both the plurality of mapped navigational landmarks and theat least one target trajectory may be generated based on driveinformation collected from a plurality of vehicles that traveledpreviously along the at least one road segment. The at least oneprocessor may also be programmed to receive point cloud information froma lidar system onboard the vehicle. The point cloud information may berepresentative of distances to various objects in an environment of thevehicle. The at least one processor may further be programmed to comparethe received point cloud information with at least one of the pluralityof mapped navigational landmarks in the sparse map to provide alidar-based localization of the vehicle relative to the at least onetarget trajectory. The at least one processor may also be programmed todetermine at least one navigational action for the vehicle based on thelidar-based localization of the vehicle relative to the at least onetarget trajectory. The at least one processor may further be programmedto cause the at least one navigational action to be taken by thevehicle.

In an embodiment, a method for controlling a navigation system for ahost vehicle may include receiving, from an entity remotely locatedrelative to a vehicle, a sparse map associated with at least one roadsegment to be traversed by the vehicle. The sparse map may include aplurality of mapped navigational landmarks and at least one targettrajectory. Both the plurality of mapped navigational landmarks and theat least one target trajectory may be generated based on driveinformation collected from a plurality of vehicles that traveledpreviously along the at least one road segment. The method may alsoinclude receiving point cloud information from a lidar system onboardthe vehicle. The point cloud information being representative ofdistances to various objects in an environment of the vehicle. Themethod may also include comparing the received point cloud informationwith at least one of the plurality of mapped navigational landmarks inthe sparse map to provide a lidar-based localization of the vehiclerelative to the at least one target trajectory. The method may furtherinclude determining at least one navigational action for the vehiclebased on the lidar-based localization of the vehicle relative to the atleast one target trajectory. The method may also include causing the atleast one navigational action to be taken by the vehicle.

In an embodiment, a navigation system for a host vehicle may include atleast one processor programmed to receive from a camera onboard the hostvehicle at least one captured image representative of an environment ofthe host vehicle. The at least one processor may also be programmed toreceive point cloud information from a LIDAR system onboard the hostvehicle. The point cloud information may be representative of distancesto various objects in the environment of the host vehicle. The at leastone processor may further be programmed to correlate the point cloudinformation with the at least one captured image to provide per-pixeldepth information for one or more regions of the at least one capturedimage. The at least one processor may also be programmed to determine atleast one navigational action for the host vehicle based on theper-pixel depth information for one or more regions of the at least onecaptured image, and cause the at least one navigational action to betaken by the host vehicle.

In an embodiment, a method for determining a navigational action for ahost vehicle may include receiving point cloud information from a LIDARsystem onboard the host vehicle. The point cloud information may berepresentative of distances to a plurality of objects in the environmentof the host vehicle. The method may also include correlating the pointcloud information with the at least one captured image to provideper-pixel depth information for one or more regions of the at least onecaptured image. The method may further include determining at least onenavigational action for the host vehicle based on the per-pixel depthinformation for one or more regions of the at least one captured image,and causing the at least one navigational action to be taken by the hostvehicle.

In an embodiment, a navigation system for a host vehicle may include atleast one processor programmed to receive from a camera onboard the hostvehicle at least one captured image representative of an environment ofthe host vehicle. The camera may be positioned at a first locationrelative to the host vehicle. The at least one processor may also beprogrammed to receive point cloud information from a LIDAR systemonboard the host vehicle. The point cloud information may berepresentative of distances to various objects in an environment of thehost vehicle. The LIDAR system may be positioned at a second locationrelative to the host vehicle, and the second location may be differentfrom the first location. A field of view of the camera may at leastpartially overlap with a field of view of the LIDAR system to provide ashared field of view region. The at least one processor may further beprogrammed to analyze the at least one captured image and the receivedpoint cloud information to detect one or more objects in the sharedfield of view region. The detected one or more objects may berepresented in only one of the at least one captured image or thereceived point cloud information. The at least one processor may also beprogrammed to determine whether a vantage point difference between thefirst location of the camera and the second location of the LIDAR systemaccounts for the one or more detected objects being represented in onlyone of the at least one captured image or the received point cloudinformation. The at least one processor may be programmed to cause atleast one remedial action to be taken if the vantage point differencedoes not account for the one or more detected objects being representedin only one of the at least one captured image or the received pointcloud information. The at least one processor may be programmed todetermine at least one navigational action to be taken by the hostvehicle based on the one or more detected objects and cause the at leastone navigational action to be taken by the host vehicle if the vantagepoint difference does account for the one or more detected objects beingrepresented in only one of the at least one captured image or thereceived point cloud information.

In an embodiment, a method for determining a navigational action for ahost vehicle may include receiving from a camera onboard the hostvehicle at least one captured image representative of an environment ofthe host vehicle. The camera may be positioned at a first locationrelative to the host vehicle. The method may also include receivingpoint cloud information from a LIDAR system onboard the host vehicle.The point cloud information may be representative of distances tovarious objects in an environment of the host vehicle. The LIDAR systemmay be positioned at a second location relative to the host vehicle, andthe second location may be different from the first location. A field ofview of the camera may at least partially overlap with a field of viewof the LIDAR system to provide a shared field of view region. The methodmay further include analyzing the at least one captured image and thereceived point cloud information to detect one or more objects in theshared field of view region. The detected one or more objects may berepresented in only one of the at least one captured image or thereceived point cloud information. The method may also includedetermining whether a vantage point difference between the firstlocation of the camera and the second location of the LIDAR systemaccounts for the one or more detected objects being represented in onlyone of the at least one captured image or the received point cloudinformation. The method may further include, if the vantage pointdifference does not account for the one or more detected objects beingrepresented in only one of the at least one captured image or thereceived point cloud information, then causing at least one remedialaction to be taken. The method may also include, if the vantage pointdifference does account for the one or more detected objects beingrepresented in only one of the at least one captured image or thereceived point cloud information, then determining at least onenavigational action to be taken by the host vehicle based on the one ormore detected objects and cause the at least one navigational action tobe taken by the host vehicle.

In an embodiment, a navigation system for a host vehicle may include atleast one processor programmed to receive from a center camera onboardthe host vehicle at least one captured center image including arepresentation of at least a portion of an environment of the hostvehicle, receive from a left surround camera onboard the host vehicle atleast one captured left surround image including a representation of atleast a portion of the environment of the host vehicle, and receive froma right surround camera onboard the host vehicle at least one capturedright surround image including a representation of at least a portion ofthe environment of the host vehicle. A field of view of the centercamera may at least partially overlap with both a field of view of theleft surround camera and a field of view of the right surround camera.The at least one processor may also be programmed to provide the atleast one captured center image, the at least one captured left surroundimage, and the at least one captured right surround image to an analysismodule configured to generate an output relative to the at least onecaptured center image based on analysis of the at least one capturedcenter image, the at least one captured left surround image, and the atleast one captured right surround image. The generated output includesper-pixel depth information for at least one region of the capturedcenter image. The at least one processor may further be programmed tocause at least one navigational action by the host vehicle based on thegenerated output including the per-pixel depth information for the atleast one region of the captured center image.

In an embodiment, a method for determining a navigational action for ahost vehicle may include receiving from a center camera onboard the hostvehicle at least one captured center image including a representation ofat least a portion of an environment of the host vehicle, receive from aleft surround camera onboard the host vehicle at least one captured leftsurround image including a representation of at least a portion of theenvironment of the host vehicle, and receive from a right surroundcamera onboard the host vehicle at least one captured right surroundimage including a representation of at least a portion of theenvironment of the host vehicle. A field of view of the center camera atleast partially overlaps with both a field of view of the left surroundcamera and a field of view of the right surround camera. The method mayalso include providing the at least one captured center image, the atleast one captured left surround image, and the at least one capturedright surround image to an analysis module configured to generate anoutput relative to the at least one captured center image based onanalysis of the at least one captured center image, the at least onecaptured left surround image, and the at least one captured rightsurround image. The generated output includes per-pixel depthinformation for at least one region of the captured center image. Themethod may further include causing at least one navigational action bythe host vehicle based on the generated output including the per-pixeldepth information for the at least one region of the captured centerimage.

Consistent with other disclosed embodiments, non-transitorycomputer-readable storage media may store program instructions, whichare executed by at least one processing device and perform any of themethods described herein.

The foregoing general description and the following detailed descriptionare exemplary and explanatory only and are not restrictive of theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this disclosure, illustrate various disclosed embodiments. Inthe drawings:

FIG. 1 is a diagrammatic representation of an exemplary systemconsistent with the disclosed embodiments.

FIG. 2A is a diagrammatic side view representation of an exemplaryvehicle including a system consistent with the disclosed embodiments.

FIG. 2B is a diagrammatic top view representation of the vehicle andsystem shown in FIG. 2A consistent with the disclosed embodiments.

FIG. 2C is a diagrammatic top view representation of another embodimentof a vehicle including a system consistent with the disclosedembodiments.

FIG. 2D is a diagrammatic top view representation of yet anotherembodiment of a vehicle including a system consistent with the disclosedembodiments.

FIG. 2E is a diagrammatic top view representation of yet anotherembodiment of a vehicle including a system consistent with the disclosedembodiments.

FIG. 2F is a diagrammatic representation of exemplary vehicle controlsystems consistent with the disclosed embodiments.

FIG. 3A is a diagrammatic representation of an interior of a vehicleincluding a rearview mirror and a user interface for a vehicle imagingsystem consistent with the disclosed embodiments.

FIG. 3B is an illustration of an example of a camera mount that isconfigured to be positioned behind a rearview mirror and against avehicle windshield consistent with the disclosed embodiments.

FIG. 3C is an illustration of the camera mount shown in FIG. 3B from adifferent perspective consistent with the disclosed embodiments.

FIG. 3D is an illustration of an example of a camera mount that isconfigured to be positioned behind a rearview mirror and against avehicle windshield consistent with the disclosed embodiments.

FIG. 4 is an exemplary block diagram of a memory configured to storeinstructions for performing one or more operations consistent with thedisclosed embodiments.

FIG. 5A is a flowchart showing an exemplary process for causing one ormore navigational responses based on monocular image analysis consistentwith disclosed embodiments.

FIG. 5B is a flowchart showing an exemplary process for detecting one ormore vehicles and/or pedestrians in a set of images consistent with thedisclosed embodiments.

FIG. 5C is a flowchart showing an exemplary process for detecting roadmarks and/or lane geometry information in a set of images consistentwith the disclosed embodiments.

FIG. 5D is a flowchart showing an exemplary process for detectingtraffic lights in a set of images consistent with the disclosedembodiments.

FIG. 5E is a flowchart showing an exemplary process for causing one ormore navigational responses based on a vehicle path consistent with thedisclosed embodiments.

FIG. 5F is a flowchart showing an exemplary process for determiningwhether a leading vehicle is changing lanes consistent with thedisclosed embodiments.

FIG. 6 is a flowchart showing an exemplary process for causing one ormore navigational responses based on stereo image analysis consistentwith the disclosed embodiments.

FIG. 7 is a flowchart showing an exemplary process for causing one ormore navigational responses based on an analysis of three sets of imagesconsistent with the disclosed embodiments.

FIG. 8 shows a sparse map for providing autonomous vehicle navigation,consistent with the disclosed embodiments.

FIG. 9A illustrates a polynomial representation of a portions of a roadsegment consistent with the disclosed embodiments.

FIG. 9B illustrates a curve in three-dimensional space representing atarget trajectory of a vehicle, for a particular road segment, includedin a sparse map consistent with the disclosed embodiments.

FIG. 10 illustrates example landmarks that may be included in sparse mapconsistent with the disclosed embodiments.

FIG. 11A shows polynomial representations of trajectories consistentwith the disclosed embodiments.

FIGS. 11B and 11C show target trajectories along a multi-lane roadconsistent with disclosed embodiments.

FIG. 11D shows an example road signature profile consistent withdisclosed embodiments.

FIG. 12 is a schematic illustration of a system that uses crowd sourcingdata received from a plurality of vehicles for autonomous vehiclenavigation, consistent with the disclosed embodiments.

FIG. 13 illustrates an example autonomous vehicle road navigation modelrepresented by a plurality of three dimensional splines, consistent withthe disclosed embodiments.

FIG. 14 shows a map skeleton generated from combining locationinformation from many drives, consistent with the disclosed embodiments.

FIG. 15 shows an example of a longitudinal alignment of two drives withexample signs as landmarks, consistent with the disclosed embodiments.

FIG. 16 shows an example of a longitudinal alignment of many drives withan example sign as a landmark, consistent with the disclosedembodiments.

FIG. 17 is a schematic illustration of a system for generating drivedata using a camera, a vehicle, and a server, consistent with thedisclosed embodiments.

FIG. 18 is a schematic illustration of a system for crowdsourcing asparse map, consistent with the disclosed embodiments.

FIG. 19 is a flowchart showing an exemplary process for generating asparse map for autonomous vehicle navigation along a road segment,consistent with the disclosed embodiments.

FIG. 20 illustrates a block diagram of a server consistent with thedisclosed embodiments.

FIG. 21 illustrates a block diagram of a memory consistent with thedisclosed embodiments.

FIG. 22 illustrates a process of clustering vehicle trajectoriesassociated with vehicles, consistent with the disclosed embodiments.

FIG. 23 illustrates a navigation system for a vehicle, which may be usedfor autonomous navigation, consistent with the disclosed embodiments.

FIGS. 24A, 24B, 24C, and 24D illustrate exemplary lane marks that may bedetected consistent with the disclosed embodiments.

FIG. 24E shows exemplary mapped lane marks consistent with the disclosedembodiments.

FIG. 24F shows an exemplary anomaly associated with detecting a lanemark consistent with the disclosed embodiments.

FIG. 25A shows an exemplary image of a vehicle's surrounding environmentfor navigation based on the mapped lane marks consistent with thedisclosed embodiments.

FIG. 25B illustrates a lateral localization correction of a vehiclebased on mapped lane marks in a road navigation model consistent withthe disclosed embodiments.

FIGS. 25C and 25D provide conceptual representations of a localizationtechnique for locating a host vehicle along a target trajectory usingmapped features included in a sparse map.

FIG. 26A is a flowchart showing an exemplary process for mapping a lanemark for use in autonomous vehicle navigation consistent with disclosedembodiments.

FIG. 26B is a flowchart showing an exemplary process for autonomouslynavigating a host vehicle along a road segment using mapped lane marksconsistent with disclosed embodiments.

FIG. 27 illustrates an exemplary system for determining a velocity of anobject consistent with disclosed embodiments.

FIG. 28 illustrates an exemplary server consistent with disclosedembodiments.

FIG. 29 illustrates an exemplary vehicle consistent with disclosedembodiments.

FIG. 30A illustrates exemplary objects in a field of view associatedwith a navigation system consistent with disclosed embodiments.

FIG. 30B illustrates exemplary objects in the field of view associatedwith a navigation system consistent with disclosed embodiments.

FIG. 31 is a flowchart showing an exemplary process for determining avelocity of an object consistent with disclosed embodiments.

FIG. 32 illustrates an exemplary system for determining a navigationalaction for a host vehicle consistent with disclosed embodiments.

FIG. 33 illustrates an exemplary server consistent with disclosedembodiments.

FIG. 34 illustrates an exemplary vehicle consistent with disclosedembodiments.

FIG. 35A illustrates an exemplary road segment consistent with disclosedembodiments.

FIG. 35B illustrates an exemplary sparse map associated with anexemplary road segment consistent with disclosed embodiments.

FIG. 35C illustrates an exemplary road segment consistent with disclosedembodiments.

FIG. 36 is a flowchart showing an exemplary process for determining anavigational action for a host vehicle consistent with disclosedembodiments.

FIG. 37 illustrates an exemplary vehicle consistent with disclosedembodiments.

FIG. 38 is a flowchart showing an exemplary process for determining anavigational action for a host vehicle consistent with disclosedembodiments.

FIGS. 39A and 39B illustrate exemplary point cloud information andimages consistent with disclosed embodiments.

FIG. 40 illustrates an exemplary vehicle consistent with disclosedembodiments.

FIG. 41 is a flowchart showing an exemplary process for determining anavigational action for a host vehicle consistent with disclosedembodiments.

FIG. 42 illustrates a host vehicle in an exemplary environmentconsistent with disclosed embodiments.

FIG. 43 illustrates an exemplary vehicle consistent with disclosedembodiments.

FIG. 44 illustrates an exemplary vehicle consistent with disclosedembodiments.

FIG. 45 is a flowchart showing an exemplary process for determining anavigational action for a host vehicle consistent with disclosedembodiments.

DETAILED DESCRIPTION

The following detailed description refers to the accompanying drawings.Wherever possible, the same reference numbers are used in the drawingsand the following description to refer to the same or similar parts.While several illustrative embodiments are described herein,modifications, adaptations and other implementations are possible. Forexample, substitutions, additions or modifications may be made to thecomponents illustrated in the drawings, and the illustrative methodsdescribed herein may be modified by substituting, reordering, removing,or adding steps to the disclosed methods. Accordingly, the followingdetailed description is not limited to the disclosed embodiments andexamples. Instead, the proper scope is defined by the appended claims.

Autonomous Vehicle Overview

As used throughout this disclosure, the term “autonomous vehicle” refersto a vehicle capable of implementing at least one navigational changewithout driver input. A “navigational change” refers to a change in oneor more of steering, braking, or acceleration of the vehicle. To beautonomous, a vehicle need not be fully automatic (e.g., fully operationwithout a driver or without driver input). Rather, an autonomous vehicleincludes those that can operate under driver control during certain timeperiods and without driver control during other time periods. Autonomousvehicles may also include vehicles that control only some aspects ofvehicle navigation, such as steering (e.g., to maintain a vehicle coursebetween vehicle lane constraints), but may leave other aspects to thedriver (e.g., braking). In some cases, autonomous vehicles may handlesome or all aspects of braking, speed control, and/or steering of thevehicle.

As human drivers typically rely on visual cues and observations tocontrol a vehicle, transportation infrastructures are built accordingly,with lane markings, traffic signs, and traffic lights are all designedto provide visual information to drivers. In view of these designcharacteristics of transportation infrastructures, an autonomous vehiclemay include a camera and a processing unit that analyzes visualinformation captured from the environment of the vehicle. The visualinformation may include, for example, components of the transportationinfrastructure (e.g., lane markings, traffic signs, traffic lights,etc.) that are observable by drivers and other obstacles (e.g., othervehicles, pedestrians, debris, etc.). Additionally, an autonomousvehicle may also use stored information, such as information thatprovides a model of the vehicle's environment when navigating. Forexample, the vehicle may use GPS data, sensor data (e.g., from anaccelerometer, a speed sensor, a suspension sensor, etc.), and/or othermap data to provide information related to its environment while thevehicle is traveling, and the vehicle (as well as other vehicles) mayuse the information to localize itself on the model.

In some embodiments in this disclosure, an autonomous vehicle may useinformation obtained while navigating (e.g., from a camera, GPS device,an accelerometer, a speed sensor, a suspension sensor, etc.). In otherembodiments, an autonomous vehicle may use information obtained frompast navigations by the vehicle (or by other vehicles) while navigating.In yet other embodiments, an autonomous vehicle may use a combination ofinformation obtained while navigating and information obtained from pastnavigations. The following sections provide an overview of a systemconsistent with the disclosed embodiments, followed by an overview of aforward-facing imaging system and methods consistent with the system.The sections that follow disclose systems and methods for constructing,using, and updating a sparse map for autonomous vehicle navigation.

System Overview

FIG. 1 is a block diagram representation of a system 100 consistent withthe exemplary disclosed embodiments. System 100 may include variouscomponents depending on the requirements of a particular implementation.In some embodiments, system 100 may include a processing unit 110, animage acquisition unit 120, a position sensor 130, one or more memoryunits 140, 150, a map database 160, a user interface 170, and a wirelesstransceiver 172. Processing unit 110 may include one or more processingdevices. In some embodiments, processing unit 110 may include anapplications processor 180, an image processor 190, or any othersuitable processing device. Similarly, image acquisition unit 120 mayinclude any number of image acquisition devices and components dependingon the requirements of a particular application. In some embodiments,image acquisition unit 120 may include one or more image capture devices(e.g., cameras), such as image capture device 122, image capture device124, and image capture device 126. System 100 may also include a datainterface 128 communicatively connecting processing device 110 to imageacquisition device 120. For example, data interface 128 may include anywired and/or wireless link or links for transmitting image data acquiredby image accusation device 120 to processing unit 110.

Wireless transceiver 172 may include one or more devices configured toexchange transmissions over an air interface to one or more networks(e.g., cellular, the Internet, etc.) by use of a radio frequency,infrared frequency, magnetic field, or an electric field. Wirelesstransceiver 172 may use any known standard to transmit and/or receivedata (e.g., Wi-Fi, Bluetooth®, Bluetooth Smart, 802.15.4, ZigBee, etc.).Such transmissions can include communications from the host vehicle toone or more remotely located servers. Such transmissions may alsoinclude communications (one-way or two-way) between the host vehicle andone or more target vehicles in an environment of the host vehicle (e.g.,to facilitate coordination of navigation of the host vehicle in view ofor together with target vehicles in the environment of the hostvehicle), or even a broadcast transmission to unspecified recipients ina vicinity of the transmitting vehicle.

Both applications processor 180 and image processor 190 may includevarious types of processing devices. For example, either or both ofapplications processor 180 and image processor 190 may include amicroprocessor, preprocessors (such as an image preprocessor), agraphics processing unit (GPU), a central processing unit (CPU), supportcircuits, digital signal processors, integrated circuits, memory, or anyother types of devices suitable for running applications and for imageprocessing and analysis. In some embodiments, applications processor 180and/or image processor 190 may include any type of single or multi-coreprocessor, mobile device microcontroller, central processing unit, etc.Various processing devices may be used, including, for example,processors available from manufacturers such as Intel®, AMD®, etc., orGPUs available from manufacturers such as NVIDIA®, ATI®, etc. and mayinclude various architectures (e.g., x86 processor, ARM®, etc.).

In some embodiments, applications processor 180 and/or image processor190 may include any of the EyeQ series of processor chips available fromMobileye®. These processor designs each include multiple processingunits with local memory and instruction sets. Such processors mayinclude video inputs for receiving image data from multiple imagesensors and may also include video out capabilities. In one example, theEyeQ2® uses 90 nm-micron technology operating at 332 Mhz. The EyeQ2®architecture consists of two floating point, hyper-thread 32-bit RISCCPUs (MIPS32® 34K® cores), five Vision Computing Engines (VCE), threeVector Microcode Processors (VMP®), Denali 64-bit Mobile DDR Controller,128-bit internal Sonics Interconnect, dual 16-bit Video input and 18-bitVideo output controllers, 16 channels DMA and several peripherals. TheMIPS34K CPU manages the five VCEs, three VMP™ and the DMA, the secondMIPS34K CPU and the multi-channel DMA as well as the other peripherals.The five VCEs, three VMP® and the MIPS34K CPU can perform intensivevision computations required by multi-function bundle applications. Inanother example, the EyeQ3®, which is a third generation processor andis six times more powerful that the EyeQ2®, may be used in the disclosedembodiments. In other examples, the EyeQ4® and/or the EyeQ5® may be usedin the disclosed embodiments. Of course, any newer or future EyeQprocessing devices may also be used together with the disclosedembodiments.

Any of the processing devices disclosed herein may be configured toperform certain functions. Configuring a processing device, such as anyof the described EyeQ processors or other controller or microprocessor,to perform certain functions may include programming of computerexecutable instructions and making those instructions available to theprocessing device for execution during operation of the processingdevice. In some embodiments, configuring a processing device may includeprogramming the processing device directly with architecturalinstructions. For example, processing devices such as field-programmablegate arrays (FPGAs), application-specific integrated circuits (ASICs),and the like may be configured using, for example, one or more hardwaredescription languages (HDLs).

In other embodiments, configuring a processing device may includestoring executable instructions on a memory that is accessible to theprocessing device during operation. For example, the processing devicemay access the memory to obtain and execute the stored instructionsduring operation. In either case, the processing device configured toperform the sensing, image analysis, and/or navigational functionsdisclosed herein represents a specialized hardware-based system incontrol of multiple hardware based components of a host vehicle.

While FIG. 1 depicts two separate processing devices included inprocessing unit 110, more or fewer processing devices may be used. Forexample, in some embodiments, a single processing device may be used toaccomplish the tasks of applications processor 180 and image processor190. In other embodiments, these tasks may be performed by more than twoprocessing devices. Further, in some embodiments, system 100 may includeone or more of processing unit 110 without including other components,such as image acquisition unit 120.

Processing unit 110 may comprise various types of devices. For example,processing unit 110 may include various devices, such as a controller,an image preprocessor, a central processing unit (CPU), a graphicsprocessing unit (GPU), support circuits, digital signal processors,integrated circuits, memory, or any other types of devices for imageprocessing and analysis. The image preprocessor may include a videoprocessor for capturing, digitizing and processing the imagery from theimage sensors. The CPU may comprise any number of microcontrollers ormicroprocessors. The GPU may also comprise any number ofmicrocontrollers or microprocessors. The support circuits may be anynumber of circuits generally well known in the art, including cache,power supply, clock and input-output circuits. The memory may storesoftware that, when executed by the processor, controls the operation ofthe system. The memory may include databases and image processingsoftware. The memory may comprise any number of random access memories,read only memories, flash memories, disk drives, optical storage, tapestorage, removable storage and other types of storage. In one instance,the memory may be separate from the processing unit 110. In anotherinstance, the memory may be integrated into the processing unit 110.

Each memory 140, 150 may include software instructions that whenexecuted by a processor (e.g., applications processor 180 and/or imageprocessor 190), may control operation of various aspects of system 100.These memory units may include various databases and image processingsoftware, as well as a trained system, such as a neural network, or adeep neural network, for example. The memory units may include randomaccess memory (RAM), read only memory (ROM), flash memory, disk drives,optical storage, tape storage, removable storage and/or any other typesof storage. In some embodiments, memory units 140, 150 may be separatefrom the applications processor 180 and/or image processor 190. In otherembodiments, these memory units may be integrated into applicationsprocessor 180 and/or image processor 190.

Position sensor 130 may include any type of device suitable fordetermining a location associated with at least one component of system100. In some embodiments, position sensor 130 may include a GPSreceiver. Such receivers can determine a user position and velocity byprocessing signals broadcasted by global positioning system satellites.Position information from position sensor 130 may be made available toapplications processor 180 and/or image processor 190.

In some embodiments, system 100 may include components such as a speedsensor (e.g., a tachometer, a speedometer) for measuring a speed ofvehicle 200 and/or an accelerometer (either single axis or multiaxis)for measuring acceleration of vehicle 200.

User interface 170 may include any device suitable for providinginformation to or for receiving inputs from one or more users of system100. In some embodiments, user interface 170 may include user inputdevices, including, for example, a touchscreen, microphone, keyboard,pointer devices, track wheels, cameras, knobs, buttons, etc. With suchinput devices, a user may be able to provide information inputs orcommands to system 100 by typing instructions or information, providingvoice commands, selecting menu options on a screen using buttons,pointers, or eye-tracking capabilities, or through any other suitabletechniques for communicating information to system 100.

User interface 170 may be equipped with one or more processing devicesconfigured to provide and receive information to or from a user andprocess that information for use by, for example, applications processor180. In some embodiments, such processing devices may executeinstructions for recognizing and tracking eye movements, receiving andinterpreting voice commands, recognizing and interpreting touches and/orgestures made on a touchscreen, responding to keyboard entries or menuselections, etc. In some embodiments, user interface 170 may include adisplay, speaker, tactile device, and/or any other devices for providingoutput information to a user.

Map database 160 may include any type of database for storing map datauseful to system 100. In some embodiments, map database 160 may includedata relating to the position, in a reference coordinate system, ofvarious items, including roads, water features, geographic features,businesses, points of interest, restaurants, gas stations, etc. Mapdatabase 160 may store not only the locations of such items, but alsodescriptors relating to those items, including, for example, namesassociated with any of the stored features. In some embodiments, mapdatabase 160 may be physically located with other components of system100. Alternatively or additionally, map database 160 or a portionthereof may be located remotely with respect to other components ofsystem 100 (e.g., processing unit 110). In such embodiments, informationfrom map database 160 may be downloaded over a wired or wireless dataconnection to a network (e.g., over a cellular network and/or theInternet, etc.). In some cases, map database 160 may store a sparse datamodel including polynomial representations of certain road features(e.g., lane markings) or target trajectories for the host vehicle.Systems and methods of generating such a map are discussed below withreferences to FIGS. 8-19 .

Image capture devices 122, 124, and 126 may each include any type ofdevice suitable for capturing at least one image from an environment.Moreover, any number of image capture devices may be used to acquireimages for input to the image processor. Some embodiments may includeonly a single image capture device, while other embodiments may includetwo, three, or even four or more image capture devices. Image capturedevices 122, 124, and 126 will be further described with reference toFIGS. 2B-2E, below.

System 100, or various components thereof, may be incorporated intovarious different platforms. In some embodiments, system 100 may beincluded on a vehicle 200, as shown in FIG. 2A. For example, vehicle 200may be equipped with a processing unit 110 and any of the othercomponents of system 100, as described above relative to FIG. 1 . Whilein some embodiments vehicle 200 may be equipped with only a single imagecapture device (e.g., camera), in other embodiments, such as thosediscussed in connection with FIGS. 2B-2E, multiple image capture devicesmay be used. For example, either of image capture devices 122 and 124 ofvehicle 200, as shown in FIG. 2A, may be part of an ADAS (AdvancedDriver Assistance Systems) imaging set.

The image capture devices included on vehicle 200 as part of the imageacquisition unit 120 may be positioned at any suitable location. In someembodiments, as shown in FIGS. 2A-2E and 3A-3C, image capture device 122may be located in the vicinity of the rearview mirror. This position mayprovide a line of sight similar to that of the driver of vehicle 200,which may aid in determining what is and is not visible to the driver.Image capture device 122 may be positioned at any location near therearview mirror, but placing image capture device 122 on the driver sideof the mirror may further aid in obtaining images representative of thedriver's field of view and/or line of sight.

Other locations for the image capture devices of image acquisition unit120 may also be used. For example, image capture device 124 may belocated on or in a bumper of vehicle 200. Such a location may beespecially suitable for image capture devices having a wide field ofview. The line of sight of bumper-located image capture devices can bedifferent from that of the driver and, therefore, the bumper imagecapture device and driver may not always see the same objects. The imagecapture devices (e.g., image capture devices 122, 124, and 126) may alsobe located in other locations. For example, the image capture devicesmay be located on or in one or both of the side mirrors of vehicle 200,on the roof of vehicle 200, on the hood of vehicle 200, on the trunk ofvehicle 200, on the sides of vehicle 200, mounted on, positioned behind,or positioned in front of any of the windows of vehicle 200, and mountedin or near light figures on the front and/or back of vehicle 200, etc.

In addition to image capture devices, vehicle 200 may include variousother components of system 100. For example, processing unit 110 may beincluded on vehicle 200 either integrated with or separate from anengine control unit (ECU) of the vehicle. Vehicle 200 may also beequipped with a position sensor 130, such as a GPS receiver and may alsoinclude a map database 160 and memory units 140 and 150.

As discussed earlier, wireless transceiver 172 may and/or receive dataover one or more networks (e.g., cellular networks, the Internet, etc.).For example, wireless transceiver 172 may upload data collected bysystem 100 to one or more servers, and download data from the one ormore servers. Via wireless transceiver 172, system 100 may receive, forexample, periodic or on demand updates to data stored in map database160, memory 140, and/or memory 150. Similarly, wireless transceiver 172may upload any data (e.g., images captured by image acquisition unit120, data received by position sensor 130 or other sensors, vehiclecontrol systems, etc.) from by system 100 and/or any data processed byprocessing unit 110 to the one or more servers.

System 100 may upload data to a server (e.g., to the cloud) based on aprivacy level setting. For example, system 100 may implement privacylevel settings to regulate or limit the types of data (includingmetadata) sent to the server that may uniquely identify a vehicle and ordriver/owner of a vehicle. Such settings may be set by user via, forexample, wireless transceiver 172, be initialized by factory defaultsettings, or by data received by wireless transceiver 172.

In some embodiments, system 100 may upload data according to a “high”privacy level, and under setting a setting, system 100 may transmit data(e.g., location information related to a route, captured images, etc.)without any details about the specific vehicle and/or driver/owner. Forexample, when uploading data according to a “high” privacy setting,system 100 may not include a vehicle identification number (VIN) or aname of a driver or owner of the vehicle, and may instead of transmitdata, such as captured images and/or limited location informationrelated to a route.

Other privacy levels are contemplated. For example, system 100 maytransmit data to a server according to an “intermediate” privacy leveland include additional information not included under a “high” privacylevel, such as a make and/or model of a vehicle and/or a vehicle type(e.g., a passenger vehicle, sport utility vehicle, truck, etc.). In someembodiments, system 100 may upload data according to a “low” privacylevel. Under a “low” privacy level setting, system 100 may upload dataand include information sufficient to uniquely identify a specificvehicle, owner/driver, and/or a portion or entirely of a route traveledby the vehicle. Such “low” privacy level data may include one or moreof, for example, a VIN, a driver/owner name, an origination point of avehicle prior to departure, an intended destination of the vehicle, amake and/or model of the vehicle, a type of the vehicle, etc.

FIG. 2A is a diagrammatic side view representation of an exemplaryvehicle imaging system consistent with the disclosed embodiments. FIG.2B is a diagrammatic top view illustration of the embodiment shown inFIG. 2A. As illustrated in FIG. 2B, the disclosed embodiments mayinclude a vehicle 200 including in its body a system 100 with a firstimage capture device 122 positioned in the vicinity of the rearviewmirror and/or near the driver of vehicle 200, a second image capturedevice 124 positioned on or in a bumper region (e.g., one of bumperregions 210) of vehicle 200, and a processing unit 110.

As illustrated in FIG. 2C, image capture devices 122 and 124 may both bepositioned in the vicinity of the rearview mirror and/or near the driverof vehicle 200. Additionally, while two image capture devices 122 and124 are shown in FIGS. 2B and 2C, it should be understood that otherembodiments may include more than two image capture devices. Forexample, in the embodiments shown in FIGS. 2D and 2E, first, second, andthird image capture devices 122, 124, and 126, are included in thesystem 100 of vehicle 200.

As illustrated in FIG. 2D, image capture device 122 may be positioned inthe vicinity of the rearview mirror and/or near the driver of vehicle200, and image capture devices 124 and 126 may be positioned on or in abumper region (e.g., one of bumper regions 210) of vehicle 200. And asshown in FIG. 2E, image capture devices 122, 124, and 126 may bepositioned in the vicinity of the rearview mirror and/or near the driverseat of vehicle 200. The disclosed embodiments are not limited to anyparticular number and configuration of the image capture devices, andthe image capture devices may be positioned in any appropriate locationwithin and/or on vehicle 200.

It is to be understood that the disclosed embodiments are not limited tovehicles and could be applied in other contexts. It is also to beunderstood that disclosed embodiments are not limited to a particulartype of vehicle 200 and may be applicable to all types of vehiclesincluding automobiles, trucks, trailers, and other types of vehicles.

The first image capture device 122 may include any suitable type ofimage capture device. Image capture device 122 may include an opticalaxis. In one instance, the image capture device 122 may include anAptina M9V024 WVGA sensor with a global shutter. In other embodiments,image capture device 122 may provide a resolution of 1280×960 pixels andmay include a rolling shutter. Image capture device 122 may includevarious optical elements. In some embodiments one or more lenses may beincluded, for example, to provide a desired focal length and field ofview for the image capture device. In some embodiments, image capturedevice 122 may be associated with a 6 mm lens or a 12 mm lens. In someembodiments, image capture device 122 may be configured to captureimages having a desired field-of-view (FOV) 202, as illustrated in FIG.2D. For example, image capture device 122 may be configured to have aregular FOV, such as within a range of 40 degrees to 56 degrees,including a 46 degree FOV, 50 degree FOV, 52 degree FOV, or greater.Alternatively, image capture device 122 may be configured to have anarrow FOV in the range of 23 to 40 degrees, such as a 28 degree FOV or36 degree FOV. In addition, image capture device 122 may be configuredto have a wide FOV in the range of 100 to 180 degrees. In someembodiments, image capture device 122 may include a wide angle bumpercamera or one with up to a 180 degree FOV. In some embodiments, imagecapture device 122 may be a 7.2M pixel image capture device with anaspect ratio of about 2:1 (e.g., H×V=3800×1900 pixels) with about 100degree horizontal FOV. Such an image capture device may be used in placeof a three image capture device configuration. Due to significant lensdistortion, the vertical FOV of such an image capture device may besignificantly less than 50 degrees in implementations in which the imagecapture device uses a radially symmetric lens. For example, such a lensmay not be radially symmetric which would allow for a vertical FOVgreater than 50 degrees with 100 degree horizontal FOV.

The first image capture device 122 may acquire a plurality of firstimages relative to a scene associated with the vehicle 200. Each of theplurality of first images may be acquired as a series of image scanlines, which may be captured using a rolling shutter. Each scan line mayinclude a plurality of pixels.

The first image capture device 122 may have a scan rate associated withacquisition of each of the first series of image scan lines. The scanrate may refer to a rate at which an image sensor can acquire image dataassociated with each pixel included in a particular scan line.

Image capture devices 122, 124, and 126 may contain any suitable typeand number of image sensors, including CCD sensors or CMOS sensors, forexample. In one embodiment, a CMOS image sensor may be employed alongwith a rolling shutter, such that each pixel in a row is read one at atime, and scanning of the rows proceeds on a row-by-row basis until anentire image frame has been captured. In some embodiments, the rows maybe captured sequentially from top to bottom relative to the frame.

In some embodiments, one or more of the image capture devices (e.g.,image capture devices 122, 124, and 126) disclosed herein may constitutea high resolution imager and may have a resolution greater than 5Mpixel, 7M pixel, 10M pixel, or greater.

The use of a rolling shutter may result in pixels in different rowsbeing exposed and captured at different times, which may cause skew andother image artifacts in the captured image frame. On the other hand,when the image capture device 122 is configured to operate with a globalor synchronous shutter, all of the pixels may be exposed for the sameamount of time and during a common exposure period. As a result, theimage data in a frame collected from a system employing a global shutterrepresents a snapshot of the entire FOV (such as FOV 202) at aparticular time. In contrast, in a rolling shutter application, each rowin a frame is exposed and data is capture at different times. Thus,moving objects may appear distorted in an image capture device having arolling shutter. This phenomenon will be described in greater detailbelow.

The second image capture device 124 and the third image capturing device126 may be any type of image capture device. Like the first imagecapture device 122, each of image capture devices 124 and 126 mayinclude an optical axis. In one embodiment, each of image capturedevices 124 and 126 may include an Aptina M9V024 WVGA sensor with aglobal shutter. Alternatively, each of image capture devices 124 and 126may include a rolling shutter. Like image capture device 122, imagecapture devices 124 and 126 may be configured to include various lensesand optical elements. In some embodiments, lenses associated with imagecapture devices 124 and 126 may provide FOVs (such as FOVs 204 and 206)that are the same as, or narrower than, a FOV (such as FOV 202)associated with image capture device 122. For example, image capturedevices 124 and 126 may have FOVs of 40 degrees, 30 degrees, 26 degrees,23 degrees, 20 degrees, or less.

Image capture devices 124 and 126 may acquire a plurality of second andthird images relative to a scene associated with the vehicle 200. Eachof the plurality of second and third images may be acquired as a secondand third series of image scan lines, which may be captured using arolling shutter. Each scan line or row may have a plurality of pixels.Image capture devices 124 and 126 may have second and third scan ratesassociated with acquisition of each of image scan lines included in thesecond and third series.

Each image capture device 122, 124, and 126 may be positioned at anysuitable position and orientation relative to vehicle 200. The relativepositioning of the image capture devices 122, 124, and 126 may beselected to aid in fusing together the information acquired from theimage capture devices. For example, in some embodiments, a FOV (such asFOV 204) associated with image capture device 124 may overlap partiallyor fully with a FOV (such as FOV 202) associated with image capturedevice 122 and a FOV (such as FOV 206) associated with image capturedevice 126.

Image capture devices 122, 124, and 126 may be located on vehicle 200 atany suitable relative heights. In one instance, there may be a heightdifference between the image capture devices 122, 124, and 126, whichmay provide sufficient parallax information to enable stereo analysis.For example, as shown in FIG. 2A, the two image capture devices 122 and124 are at different heights. There may also be a lateral displacementdifference between image capture devices 122, 124, and 126, givingadditional parallax information for stereo analysis by processing unit110, for example. The difference in the lateral displacement may bedenoted by d_(x), as shown in FIGS. 2C and 2D. In some embodiments, foreor aft displacement (e.g., range displacement) may exist between imagecapture devices 122, 124, and 126. For example, image capture device 122may be located 0.5 to 2 meters or more behind image capture device 124and/or image capture device 126. This type of displacement may enableone of the image capture devices to cover potential blind spots of theother image capture device(s).

Image capture devices 122 may have any suitable resolution capability(e.g., number of pixels associated with the image sensor), and theresolution of the image sensor(s) associated with the image capturedevice 122 may be higher, lower, or the same as the resolution of theimage sensor(s) associated with image capture devices 124 and 126. Insome embodiments, the image sensor(s) associated with image capturedevice 122 and/or image capture devices 124 and 126 may have aresolution of 640×480, 1024×768, 1280×960, or any other suitableresolution.

The frame rate (e.g., the rate at which an image capture device acquiresa set of pixel data of one image frame before moving on to capture pixeldata associated with the next image frame) may be controllable. Theframe rate associated with image capture device 122 may be higher,lower, or the same as the frame rate associated with image capturedevices 124 and 126. The frame rate associated with image capturedevices 122, 124, and 126 may depend on a variety of factors that mayaffect the timing of the frame rate. For example, one or more of imagecapture devices 122, 124, and 126 may include a selectable pixel delayperiod imposed before or after acquisition of image data associated withone or more pixels of an image sensor in image capture device 122, 124,and/or 126. Generally, image data corresponding to each pixel may beacquired according to a clock rate for the device (e.g., one pixel perclock cycle). Additionally, in embodiments including a rolling shutter,one or more of image capture devices 122, 124, and 126 may include aselectable horizontal blanking period imposed before or afteracquisition of image data associated with a row of pixels of an imagesensor in image capture device 122, 124, and/or 126. Further, one ormore of image capture devices 122, 124, and/or 126 may include aselectable vertical blanking period imposed before or after acquisitionof image data associated with an image frame of image capture device122, 124, and 126.

These timing controls may enable synchronization of frame ratesassociated with image capture devices 122, 124, and 126, even where theline scan rates of each are different. Additionally, as will bediscussed in greater detail below, these selectable timing controls,among other factors (e.g., image sensor resolution, maximum line scanrates, etc.) may enable synchronization of image capture from an areawhere the FOV of image capture device 122 overlaps with one or more FOVsof image capture devices 124 and 126, even where the field of view ofimage capture device 122 is different from the FOVs of image capturedevices 124 and 126.

Frame rate timing in image capture device 122, 124, and 126 may dependon the resolution of the associated image sensors. For example, assumingsimilar line scan rates for both devices, if one device includes animage sensor having a resolution of 640×480 and another device includesan image sensor with a resolution of 1280×960, then more time will berequired to acquire a frame of image data from the sensor having thehigher resolution.

Another factor that may affect the timing of image data acquisition inimage capture devices 122, 124, and 126 is the maximum line scan rate.For example, acquisition of a row of image data from an image sensorincluded in image capture device 122, 124, and 126 will require someminimum amount of time. Assuming no pixel delay periods are added, thisminimum amount of time for acquisition of a row of image data will berelated to the maximum line scan rate for a particular device. Devicesthat offer higher maximum line scan rates have the potential to providehigher frame rates than devices with lower maximum line scan rates. Insome embodiments, one or more of image capture devices 124 and 126 mayhave a maximum line scan rate that is higher than a maximum line scanrate associated with image capture device 122. In some embodiments, themaximum line scan rate of image capture device 124 and/or 126 may be1.25, 1.5, 1.75, or 2 times or more than a maximum line scan rate ofimage capture device 122.

In another embodiment, image capture devices 122, 124, and 126 may havethe same maximum line scan rate, but image capture device 122 may beoperated at a scan rate less than or equal to its maximum scan rate. Thesystem may be configured such that one or more of image capture devices124 and 126 operate at a line scan rate that is equal to the line scanrate of image capture device 122. In other instances, the system may beconfigured such that the line scan rate of image capture device 124and/or image capture device 126 may be 1.25, 1.5, 1.75, or 2 times ormore than the line scan rate of image capture device 122.

In some embodiments, image capture devices 122, 124, and 126 may beasymmetric. That is, they may include cameras having different fields ofview (FOV) and focal lengths. The fields of view of image capturedevices 122, 124, and 126 may include any desired area relative to anenvironment of vehicle 200, for example. In some embodiments, one ormore of image capture devices 122, 124, and 126 may be configured toacquire image data from an environment in front of vehicle 200, behindvehicle 200, to the sides of vehicle 200, or combinations thereof.

Further, the focal length associated with each image capture device 122,124, and/or 126 may be selectable (e.g., by inclusion of appropriatelenses etc.) such that each device acquires images of objects at adesired distance range relative to vehicle 200. For example, in someembodiments image capture devices 122, 124, and 126 may acquire imagesof close-up objects within a few meters from the vehicle. Image capturedevices 122, 124, and 126 may also be configured to acquire images ofobjects at ranges more distant from the vehicle (e.g., 25 m, 50 m, 100m, 150 m, or more). Further, the focal lengths of image capture devices122, 124, and 126 may be selected such that one image capture device(e.g., image capture device 122) can acquire images of objectsrelatively close to the vehicle (e.g., within 10 m or within 20 m) whilethe other image capture devices (e.g., image capture devices 124 and126) can acquire images of more distant objects (e.g., greater than 20m, 50 m, 100 m, 150 m, etc.) from vehicle 200.

According to some embodiments, the FOV of one or more image capturedevices 122, 124, and 126 may have a wide angle. For example, it may beadvantageous to have a FOV of 140 degrees, especially for image capturedevices 122, 124, and 126 that may be used to capture images of the areain the vicinity of vehicle 200. For example, image capture device 122may be used to capture images of the area to the right or left ofvehicle 200 and, in such embodiments, it may be desirable for imagecapture device 122 to have a wide FOV (e.g., at least 140 degrees).

The field of view associated with each of image capture devices 122,124, and 126 may depend on the respective focal lengths. For example, asthe focal length increases, the corresponding field of view decreases.

Image capture devices 122, 124, and 126 may be configured to have anysuitable fields of view. In one particular example, image capture device122 may have a horizontal FOV of 46 degrees, image capture device 124may have a horizontal FOV of 23 degrees, and image capture device 126may have a horizontal FOV in between 23 and 46 degrees. In anotherinstance, image capture device 122 may have a horizontal FOV of 52degrees, image capture device 124 may have a horizontal FOV of 26degrees, and image capture device 126 may have a horizontal FOV inbetween 26 and 52 degrees. In some embodiments, a ratio of the FOV ofimage capture device 122 to the FOVs of image capture device 124 and/orimage capture device 126 may vary from 1.5 to 2.0. In other embodiments,this ratio may vary between 1.25 and 2.25.

System 100 may be configured so that a field of view of image capturedevice 122 overlaps, at least partially or fully, with a field of viewof image capture device 124 and/or image capture device 126. In someembodiments, system 100 may be configured such that the fields of viewof image capture devices 124 and 126, for example, fall within (e.g.,are narrower than) and share a common center with the field of view ofimage capture device 122. In other embodiments, the image capturedevices 122, 124, and 126 may capture adjacent FOVs or may have partialoverlap in their FOVs. In some embodiments, the fields of view of imagecapture devices 122, 124, and 126 may be aligned such that a center ofthe narrower FOV image capture devices 124 and/or 126 may be located ina lower half of the field of view of the wider FOV device 122.

FIG. 2F is a diagrammatic representation of exemplary vehicle controlsystems, consistent with the disclosed embodiments. As indicated in FIG.2F, vehicle 200 may include throttling system 220, braking system 230,and steering system 240. System 100 may provide inputs (e.g., controlsignals) to one or more of throttling system 220, braking system 230,and steering system 240 over one or more data links (e.g., any wiredand/or wireless link or links for transmitting data). For example, basedon analysis of images acquired by image capture devices 122, 124, and/or126, system 100 may provide control signals to one or more of throttlingsystem 220, braking system 230, and steering system 240 to navigatevehicle 200 (e.g., by causing an acceleration, a turn, a lane shift,etc.). Further, system 100 may receive inputs from one or more ofthrottling system 220, braking system 230, and steering system 24indicating operating conditions of vehicle 200 (e.g., speed, whethervehicle 200 is braking and/or turning, etc.). Further details areprovided in connection with FIGS. 4-7 , below.

As shown in FIG. 3A, vehicle 200 may also include a user interface 170for interacting with a driver or a passenger of vehicle 200. Forexample, user interface 170 in a vehicle application may include a touchscreen 320, knobs 330, buttons 340, and a microphone 350. A driver orpassenger of vehicle 200 may also use handles (e.g., located on or nearthe steering column of vehicle 200 including, for example, turn signalhandles), buttons (e.g., located on the steering wheel of vehicle 200),and the like, to interact with system 100. In some embodiments,microphone 350 may be positioned adjacent to a rearview mirror 310.Similarly, in some embodiments, image capture device 122 may be locatednear rearview mirror 310. In some embodiments, user interface 170 mayalso include one or more speakers 360 (e.g., speakers of a vehicle audiosystem). For example, system 100 may provide various notifications(e.g., alerts) via speakers 360.

FIGS. 3B-3D are illustrations of an exemplary camera mount 370configured to be positioned behind a rearview mirror (e.g., rearviewmirror 310) and against a vehicle windshield, consistent with disclosedembodiments. As shown in FIG. 3B, camera mount 370 may include imagecapture devices 122, 124, and 126. Image capture devices 124 and 126 maybe positioned behind a glare shield 380, which may be flush against thevehicle windshield and include a composition of film and/oranti-reflective materials. For example, glare shield 380 may bepositioned such that the shield aligns against a vehicle windshieldhaving a matching slope. In some embodiments, each of image capturedevices 122, 124, and 126 may be positioned behind glare shield 380, asdepicted, for example, in FIG. 3D. The disclosed embodiments are notlimited to any particular configuration of image capture devices 122,124, and 126, camera mount 370, and glare shield 380. FIG. 3C is anillustration of camera mount 370 shown in FIG. 3B from a frontperspective.

As will be appreciated by a person skilled in the art having the benefitof this disclosure, numerous variations and/or modifications may be madeto the foregoing disclosed embodiments. For example, not all componentsare essential for the operation of system 100. Further, any componentmay be located in any appropriate part of system 100 and the componentsmay be rearranged into a variety of configurations while providing thefunctionality of the disclosed embodiments. Therefore, the foregoingconfigurations are examples and, regardless of the configurationsdiscussed above, system 100 can provide a wide range of functionality toanalyze the surroundings of vehicle 200 and navigate vehicle 200 inresponse to the analysis.

As discussed below in further detail and consistent with variousdisclosed embodiments, system 100 may provide a variety of featuresrelated to autonomous driving and/or driver assist technology. Forexample, system 100 may analyze image data, position data (e.g., GPSlocation information), map data, speed data, and/or data from sensorsincluded in vehicle 200. System 100 may collect the data for analysisfrom, for example, image acquisition unit 120, position sensor 130, andother sensors. Further, system 100 may analyze the collected data todetermine whether or not vehicle 200 should take a certain action, andthen automatically take the determined action without humanintervention. For example, when vehicle 200 navigates without humanintervention, system 100 may automatically control the braking,acceleration, and/or steering of vehicle 200 (e.g., by sending controlsignals to one or more of throttling system 220, braking system 230, andsteering system 240). Further, system 100 may analyze the collected dataand issue warnings and/or alerts to vehicle occupants based on theanalysis of the collected data. Additional details regarding the variousembodiments that are provided by system 100 are provided below.

Forward-Facing Multi-Imaging System

As discussed above, system 100 may provide drive assist functionalitythat uses a multi-camera system. The multi-camera system may use one ormore cameras facing in the forward direction of a vehicle. In otherembodiments, the multi-camera system may include one or more camerasfacing to the side of a vehicle or to the rear of the vehicle. In oneembodiment, for example, system 100 may use a two-camera imaging system,where a first camera and a second camera (e.g., image capture devices122 and 124) may be positioned at the front and/or the sides of avehicle (e.g., vehicle 200). The first camera may have a field of viewthat is greater than, less than, or partially overlapping with, thefield of view of the second camera. In addition, the first camera may beconnected to a first image processor to perform monocular image analysisof images provided by the first camera, and the second camera may beconnected to a second image processor to perform monocular imageanalysis of images provided by the second camera. The outputs (e.g.,processed information) of the first and second image processors may becombined. In some embodiments, the second image processor may receiveimages from both the first camera and second camera to perform stereoanalysis. In another embodiment, system 100 may use a three-cameraimaging system where each of the cameras has a different field of view.Such a system may, therefore, make decisions based on informationderived from objects located at varying distances both forward and tothe sides of the vehicle. References to monocular image analysis mayrefer to instances where image analysis is performed based on imagescaptured from a single point of view (e.g., from a single camera).Stereo image analysis may refer to instances where image analysis isperformed based on two or more images captured with one or morevariations of an image capture parameter. For example, captured imagessuitable for performing stereo image analysis may include imagescaptured: from two or more different positions, from different fields ofview, using different focal lengths, along with parallax information,etc.

For example, in one embodiment, system 100 may implement a three cameraconfiguration using image capture devices 122, 124, and 126. In such aconfiguration, image capture device 122 may provide a narrow field ofview (e.g., 34 degrees, or other values selected from a range of about20 to 45 degrees, etc.), image capture device 124 may provide a widefield of view (e.g., 150 degrees or other values selected from a rangeof about 100 to about 180 degrees), and image capture device 126 mayprovide an intermediate field of view (e.g., 46 degrees or other valuesselected from a range of about 35 to about 60 degrees). In someembodiments, image capture device 126 may act as a main or primarycamera. Image capture devices 122, 124, and 126 may be positioned behindrearview mirror 310 and positioned substantially side-by-side (e.g., 6cm apart). Further, in some embodiments, as discussed above, one or moreof image capture devices 122, 124, and 126 may be mounted behind glareshield 380 that is flush with the windshield of vehicle 200. Suchshielding may act to minimize the impact of any reflections from insidethe car on image capture devices 122, 124, and 126.

In another embodiment, as discussed above in connection with FIGS. 3Band 3C, the wide field of view camera (e.g., image capture device 124 inthe above example) may be mounted lower than the narrow and main fieldof view cameras (e.g., image devices 122 and 126 in the above example).This configuration may provide a free line of sight from the wide fieldof view camera. To reduce reflections, the cameras may be mounted closeto the windshield of vehicle 200, and may include polarizers on thecameras to damp reflected light.

A three camera system may provide certain performance characteristics.For example, some embodiments may include an ability to validate thedetection of objects by one camera based on detection results fromanother camera. In the three camera configuration discussed above,processing unit 110 may include, for example, three processing devices(e.g., three EyeQ series of processor chips, as discussed above), witheach processing device dedicated to processing images captured by one ormore of image capture devices 122, 124, and 126.

In a three camera system, a first processing device may receive imagesfrom both the main camera and the narrow field of view camera, andperform vision processing of the narrow FOV camera to, for example,detect other vehicles, pedestrians, lane marks, traffic signs, trafficlights, and other road objects. Further, the first processing device maycalculate a disparity of pixels between the images from the main cameraand the narrow camera and create a 3D reconstruction of the environmentof vehicle 200. The first processing device may then combine the 3Dreconstruction with 3D map data or with 3D information calculated basedon information from another camera.

The second processing device may receive images from main camera andperform vision processing to detect other vehicles, pedestrians, lanemarks, traffic signs, traffic lights, and other road objects.Additionally, the second processing device may calculate a cameradisplacement and, based on the displacement, calculate a disparity ofpixels between successive images and create a 3D reconstruction of thescene (e.g., a structure from motion). The second processing device maysend the structure from motion based 3D reconstruction to the firstprocessing device to be combined with the stereo 3D images.

The third processing device may receive images from the wide FOV cameraand process the images to detect vehicles, pedestrians, lane marks,traffic signs, traffic lights, and other road objects. The thirdprocessing device may further execute additional processing instructionsto analyze images to identify objects moving in the image, such asvehicles changing lanes, pedestrians, etc.

In some embodiments, having streams of image-based information capturedand processed independently may provide an opportunity for providingredundancy in the system. Such redundancy may include, for example,using a first image capture device and the images processed from thatdevice to validate and/or supplement information obtained by capturingand processing image information from at least a second image capturedevice.

In some embodiments, system 100 may use two image capture devices (e.g.,image capture devices 122 and 124) in providing navigation assistancefor vehicle 200 and use a third image capture device (e.g., imagecapture device 126) to provide redundancy and validate the analysis ofdata received from the other two image capture devices. For example, insuch a configuration, image capture devices 122 and 124 may provideimages for stereo analysis by system 100 for navigating vehicle 200,while image capture device 126 may provide images for monocular analysisby system 100 to provide redundancy and validation of informationobtained based on images captured from image capture device 122 and/orimage capture device 124. That is, image capture device 126 (and acorresponding processing device) may be considered to provide aredundant sub-system for providing a check on the analysis derived fromimage capture devices 122 and 124 (e.g., to provide an automaticemergency braking (AEB) system). Furthermore, in some embodiments,redundancy and validation of received data may be supplemented based oninformation received from one more sensors (e.g., radar, lidar, acousticsensors, information received from one or more transceivers outside of avehicle, etc.).

One of skill in the art will recognize that the above cameraconfigurations, camera placements, number of cameras, camera locations,etc., are examples only. These components and others described relativeto the overall system may be assembled and used in a variety ofdifferent configurations without departing from the scope of thedisclosed embodiments. Further details regarding usage of a multi-camerasystem to provide driver assist and/or autonomous vehicle functionalityfollow below.

FIG. 4 is an exemplary functional block diagram of memory 140 and/or150, which may be stored/programmed with instructions for performing oneor more operations consistent with the disclosed embodiments. Althoughthe following refers to memory 140, one of skill in the art willrecognize that instructions may be stored in memory 140 and/or 150.

As shown in FIG. 4 , memory 140 may store a monocular image analysismodule 402, a stereo image analysis module 404, a velocity andacceleration module 406, and a navigational response module 408. Thedisclosed embodiments are not limited to any particular configuration ofmemory 140. Further, application processor 180 and/or image processor190 may execute the instructions stored in any of modules 402, 404, 406,and 408 included in memory 140. One of skill in the art will understandthat references in the following discussions to processing unit 110 mayrefer to application processor 180 and image processor 190 individuallyor collectively. Accordingly, steps of any of the following processesmay be performed by one or more processing devices.

In one embodiment, monocular image analysis module 402 may storeinstructions (such as computer vision software) which, when executed byprocessing unit 110, performs monocular image analysis of a set ofimages acquired by one of image capture devices 122, 124, and 126. Insome embodiments, processing unit 110 may combine information from a setof images with additional sensory information (e.g., information fromradar, lidar, etc.) to perform the monocular image analysis. Asdescribed in connection with FIGS. 5A-5D below, monocular image analysismodule 402 may include instructions for detecting a set of featureswithin the set of images, such as lane markings, vehicles, pedestrians,road signs, highway exit ramps, traffic lights, hazardous objects, andany other feature associated with an environment of a vehicle. Based onthe analysis, system 100 (e.g., via processing unit 110) may cause oneor more navigational responses in vehicle 200, such as a turn, a laneshift, a change in acceleration, and the like, as discussed below inconnection with navigational response module 408.

In one embodiment, stereo image analysis module 404 may storeinstructions (such as computer vision software) which, when executed byprocessing unit 110, performs stereo image analysis of first and secondsets of images acquired by a combination of image capture devicesselected from any of image capture devices 122, 124, and 126. In someembodiments, processing unit 110 may combine information from the firstand second sets of images with additional sensory information (e.g.,information from radar) to perform the stereo image analysis. Forexample, stereo image analysis module 404 may include instructions forperforming stereo image analysis based on a first set of images acquiredby image capture device 124 and a second set of images acquired by imagecapture device 126. As described in connection with FIG. 6 below, stereoimage analysis module 404 may include instructions for detecting a setof features within the first and second sets of images, such as lanemarkings, vehicles, pedestrians, road signs, highway exit ramps, trafficlights, hazardous objects, and the like. Based on the analysis,processing unit 110 may cause one or more navigational responses invehicle 200, such as a turn, a lane shift, a change in acceleration, andthe like, as discussed below in connection with navigational responsemodule 408. Furthermore, in some embodiments, stereo image analysismodule 404 may implement techniques associated with a trained system(such as a neural network or a deep neural network) or an untrainedsystem, such as a system that may be configured to use computer visionalgorithms to detect and/or label objects in an environment from whichsensory information was captured and processed. In one embodiment,stereo image analysis module 404 and/or other image processing modulesmay be configured to use a combination of a trained and untrainedsystem.

In one embodiment, velocity and acceleration module 406 may storesoftware configured to analyze data received from one or more computingand electromechanical devices in vehicle 200 that are configured tocause a change in velocity and/or acceleration of vehicle 200. Forexample, processing unit 110 may execute instructions associated withvelocity and acceleration module 406 to calculate a target speed forvehicle 200 based on data derived from execution of monocular imageanalysis module 402 and/or stereo image analysis module 404. Such datamay include, for example, a target position, velocity, and/oracceleration, the position and/or speed of vehicle 200 relative to anearby vehicle, pedestrian, or road object, position information forvehicle 200 relative to lane markings of the road, and the like. Inaddition, processing unit 110 may calculate a target speed for vehicle200 based on sensory input (e.g., information from radar) and input fromother systems of vehicle 200, such as throttling system 220, brakingsystem 230, and/or steering system 240 of vehicle 200. Based on thecalculated target speed, processing unit 110 may transmit electronicsignals to throttling system 220, braking system 230, and/or steeringsystem 240 of vehicle 200 to trigger a change in velocity and/oracceleration by, for example, physically depressing the brake or easingup off the accelerator of vehicle 200.

In one embodiment, navigational response module 408 may store softwareexecutable by processing unit 110 to determine a desired navigationalresponse based on data derived from execution of monocular imageanalysis module 402 and/or stereo image analysis module 404. Such datamay include position and speed information associated with nearbyvehicles, pedestrians, and road objects, target position information forvehicle 200, and the like. Additionally, in some embodiments, thenavigational response may be based (partially or fully) on map data, apredetermined position of vehicle 200, and/or a relative velocity or arelative acceleration between vehicle 200 and one or more objectsdetected from execution of monocular image analysis module 402 and/orstereo image analysis module 404. Navigational response module 408 mayalso determine a desired navigational response based on sensory input(e.g., information from radar) and inputs from other systems of vehicle200, such as throttling system 220, braking system 230, and steeringsystem 240 of vehicle 200. Based on the desired navigational response,processing unit 110 may transmit electronic signals to throttling system220, braking system 230, and steering system 240 of vehicle 200 totrigger a desired navigational response by, for example, turning thesteering wheel of vehicle 200 to achieve a rotation of a predeterminedangle. In some embodiments, processing unit 110 may use the output ofnavigational response module 408 (e.g., the desired navigationalresponse) as an input to execution of velocity and acceleration module406 for calculating a change in speed of vehicle 200.

Furthermore, any of the modules (e.g., modules 402, 404, and 406)disclosed herein may implement techniques associated with a trainedsystem (such as a neural network or a deep neural network) or anuntrained system.

FIG. 5A is a flowchart showing an exemplary process 500A for causing oneor more navigational responses based on monocular image analysis,consistent with disclosed embodiments. At step 510, processing unit 110may receive a plurality of images via data interface 128 betweenprocessing unit 110 and image acquisition unit 120. For instance, acamera included in image acquisition unit 120 (such as image capturedevice 122 having field of view 202) may capture a plurality of imagesof an area forward of vehicle 200 (or to the sides or rear of a vehicle,for example) and transmit them over a data connection (e.g., digital,wired, USB, wireless, Bluetooth, etc.) to processing unit 110.Processing unit 110 may execute monocular image analysis module 402 toanalyze the plurality of images at step 520, as described in furtherdetail in connection with FIGS. 5B-5D below. By performing the analysis,processing unit 110 may detect a set of features within the set ofimages, such as lane markings, vehicles, pedestrians, road signs,highway exit ramps, traffic lights, and the like.

Processing unit 110 may also execute monocular image analysis module 402to detect various road hazards at step 520, such as, for example, partsof a truck tire, fallen road signs, loose cargo, small animals, and thelike. Road hazards may vary in structure, shape, size, and color, whichmay make detection of such hazards more challenging. In someembodiments, processing unit 110 may execute monocular image analysismodule 402 to perform multi-frame analysis on the plurality of images todetect road hazards. For example, processing unit 110 may estimatecamera motion between consecutive image frames and calculate thedisparities in pixels between the frames to construct a 3D-map of theroad. Processing unit 110 may then use the 3D-map to detect the roadsurface, as well as hazards existing above the road surface.

At step 530, processing unit 110 may execute navigational responsemodule 408 to cause one or more navigational responses in vehicle 200based on the analysis performed at step 520 and the techniques asdescribed above in connection with FIG. 4 . Navigational responses mayinclude, for example, a turn, a lane shift, a change in acceleration,and the like. In some embodiments, processing unit 110 may use dataderived from execution of velocity and acceleration module 406 to causethe one or more navigational responses. Additionally, multiplenavigational responses may occur simultaneously, in sequence, or anycombination thereof. For instance, processing unit 110 may cause vehicle200 to shift one lane over and then accelerate by, for example,sequentially transmitting control signals to steering system 240 andthrottling system 220 of vehicle 200. Alternatively, processing unit 110may cause vehicle 200 to brake while at the same time shifting lanes by,for example, simultaneously transmitting control signals to brakingsystem 230 and steering system 240 of vehicle 200.

FIG. 5B is a flowchart showing an exemplary process 500B for detectingone or more vehicles and/or pedestrians in a set of images, consistentwith disclosed embodiments. Processing unit 110 may execute monocularimage analysis module 402 to implement process 500B. At step 540,processing unit 110 may determine a set of candidate objectsrepresenting possible vehicles and/or pedestrians. For example,processing unit 110 may scan one or more images, compare the images toone or more predetermined patterns, and identify within each imagepossible locations that may contain objects of interest (e.g., vehicles,pedestrians, or portions thereof). The predetermined patterns may bedesigned in such a way to achieve a high rate of “false hits” and a lowrate of “misses.” For example, processing unit 110 may use a lowthreshold of similarity to predetermined patterns for identifyingcandidate objects as possible vehicles or pedestrians. Doing so mayallow processing unit 110 to reduce the probability of missing (e.g.,not identifying) a candidate object representing a vehicle orpedestrian.

At step 542, processing unit 110 may filter the set of candidate objectsto exclude certain candidates (e.g., irrelevant or less relevantobjects) based on classification criteria. Such criteria may be derivedfrom various properties associated with object types stored in adatabase (e.g., a database stored in memory 140). Properties may includeobject shape, dimensions, texture, position (e.g., relative to vehicle200), and the like. Thus, processing unit 110 may use one or more setsof criteria to reject false candidates from the set of candidateobjects.

At step 544, processing unit 110 may analyze multiple frames of imagesto determine whether objects in the set of candidate objects representvehicles and/or pedestrians. For example, processing unit 110 may tracka detected candidate object across consecutive frames and accumulateframe-by-frame data associated with the detected object (e.g., size,position relative to vehicle 200, etc.). Additionally, processing unit110 may estimate parameters for the detected object and compare theobject's frame-by-frame position data to a predicted position.

At step 546, processing unit 110 may construct a set of measurements forthe detected objects. Such measurements may include, for example,position, velocity, and acceleration values (relative to vehicle 200)associated with the detected objects. In some embodiments, processingunit 110 may construct the measurements based on estimation techniquesusing a series of time-based observations such as Kalman filters orlinear quadratic estimation (LQE), and/or based on available modelingdata for different object types (e.g., cars, trucks, pedestrians,bicycles, road signs, etc.). The Kalman filters may be based on ameasurement of an object's scale, where the scale measurement isproportional to a time to collision (e.g., the amount of time forvehicle 200 to reach the object). Thus, by performing steps 540-546,processing unit 110 may identify vehicles and pedestrians appearingwithin the set of captured images and derive information (e.g.,position, speed, size) associated with the vehicles and pedestrians.Based on the identification and the derived information, processing unit110 may cause one or more navigational responses in vehicle 200, asdescribed in connection with FIG. 5A, above.

At step 548, processing unit 110 may perform an optical flow analysis ofone or more images to reduce the probabilities of detecting a “falsehit” and missing a candidate object that represents a vehicle orpedestrian. The optical flow analysis may refer to, for example,analyzing motion patterns relative to vehicle 200 in the one or moreimages associated with other vehicles and pedestrians, and that aredistinct from road surface motion. Processing unit 110 may calculate themotion of candidate objects by observing the different positions of theobjects across multiple image frames, which are captured at differenttimes. Processing unit 110 may use the position and time values asinputs into mathematical models for calculating the motion of thecandidate objects. Thus, optical flow analysis may provide anothermethod of detecting vehicles and pedestrians that are nearby vehicle200. Processing unit 110 may perform optical flow analysis incombination with steps 540-546 to provide redundancy for detectingvehicles and pedestrians and increase the reliability of system 100.

FIG. 5C is a flowchart showing an exemplary process 500C for detectingroad marks and/or lane geometry information in a set of images,consistent with disclosed embodiments. Processing unit 110 may executemonocular image analysis module 402 to implement process 500C. At step550, processing unit 110 may detect a set of objects by scanning one ormore images. To detect segments of lane markings, lane geometryinformation, and other pertinent road marks, processing unit 110 mayfilter the set of objects to exclude those determined to be irrelevant(e.g., minor potholes, small rocks, etc.). At step 552, processing unit110 may group together the segments detected in step 550 belonging tothe same road mark or lane mark. Based on the grouping, processing unit110 may develop a model to represent the detected segments, such as amathematical model.

At step 554, processing unit 110 may construct a set of measurementsassociated with the detected segments. In some embodiments, processingunit 110 may create a projection of the detected segments from the imageplane onto the real-world plane. The projection may be characterizedusing a 3rd-degree polynomial having coefficients corresponding tophysical properties such as the position, slope, curvature, andcurvature derivative of the detected road. In generating the projection,processing unit 110 may take into account changes in the road surface,as well as pitch and roll rates associated with vehicle 200. Inaddition, processing unit 110 may model the road elevation by analyzingposition and motion cues present on the road surface. Further,processing unit 110 may estimate the pitch and roll rates associatedwith vehicle 200 by tracking a set of feature points in the one or moreimages.

At step 556, processing unit 110 may perform multi-frame analysis by,for example, tracking the detected segments across consecutive imageframes and accumulating frame-by-frame data associated with detectedsegments. As processing unit 110 performs multi-frame analysis, the setof measurements constructed at step 554 may become more reliable andassociated with an increasingly higher confidence level. Thus, byperforming steps 550, 552, 554, and 556, processing unit 110 mayidentify road marks appearing within the set of captured images andderive lane geometry information. Based on the identification and thederived information, processing unit 110 may cause one or morenavigational responses in vehicle 200, as described in connection withFIG. 5A, above.

At step 558, processing unit 110 may consider additional sources ofinformation to further develop a safety model for vehicle 200 in thecontext of its surroundings. Processing unit 110 may use the safetymodel to define a context in which system 100 may execute autonomouscontrol of vehicle 200 in a safe manner. To develop the safety model, insome embodiments, processing unit 110 may consider the position andmotion of other vehicles, the detected road edges and barriers, and/orgeneral road shape descriptions extracted from map data (such as datafrom map database 160). By considering additional sources ofinformation, processing unit 110 may provide redundancy for detectingroad marks and lane geometry and increase the reliability of system 100.

FIG. 5D is a flowchart showing an exemplary process 500D for detectingtraffic lights in a set of images, consistent with disclosedembodiments. Processing unit 110 may execute monocular image analysismodule 402 to implement process 500D. At step 560, processing unit 110may scan the set of images and identify objects appearing at locationsin the images likely to contain traffic lights. For example, processingunit 110 may filter the identified objects to construct a set ofcandidate objects, excluding those objects unlikely to correspond totraffic lights. The filtering may be done based on various propertiesassociated with traffic lights, such as shape, dimensions, texture,position (e.g., relative to vehicle 200), and the like. Such propertiesmay be based on multiple examples of traffic lights and traffic controlsignals and stored in a database. In some embodiments, processing unit110 may perform multi-frame analysis on the set of candidate objectsreflecting possible traffic lights. For example, processing unit 110 maytrack the candidate objects across consecutive image frames, estimatethe real-world position of the candidate objects, and filter out thoseobjects that are moving (which are unlikely to be traffic lights). Insome embodiments, processing unit 110 may perform color analysis on thecandidate objects and identify the relative position of the detectedcolors appearing inside possible traffic lights.

At step 562, processing unit 110 may analyze the geometry of a junction.The analysis may be based on any combination of: (i) the number of lanesdetected on either side of vehicle 200, (ii) markings (such as arrowmarks) detected on the road, and (iii) descriptions of the junctionextracted from map data (such as data from map database 160). Processingunit 110 may conduct the analysis using information derived fromexecution of monocular analysis module 402. In addition, Processing unit110 may determine a correspondence between the traffic lights detectedat step 560 and the lanes appearing near vehicle 200.

As vehicle 200 approaches the junction, at step 564, processing unit 110may update the confidence level associated with the analyzed junctiongeometry and the detected traffic lights. For instance, the number oftraffic lights estimated to appear at the junction as compared with thenumber actually appearing at the junction may impact the confidencelevel. Thus, based on the confidence level, processing unit 110 maydelegate control to the driver of vehicle 200 in order to improve safetyconditions. By performing steps 560, 562, and 564, processing unit 110may identify traffic lights appearing within the set of captured imagesand analyze junction geometry information. Based on the identificationand the analysis, processing unit 110 may cause one or more navigationalresponses in vehicle 200, as described in connection with FIG. 5A,above.

FIG. 5E is a flowchart showing an exemplary process 500E for causing oneor more navigational responses in vehicle 200 based on a vehicle path,consistent with the disclosed embodiments. At step 570, processing unit110 may construct an initial vehicle path associated with vehicle 200.The vehicle path may be represented using a set of points expressed incoordinates (x, z), and the distance d_(i) between two points in the setof points may fall in the range of 1 to 5 meters. In one embodiment,processing unit 110 may construct the initial vehicle path using twopolynomials, such as left and right road polynomials. Processing unit110 may calculate the geometric midpoint between the two polynomials andoffset each point included in the resultant vehicle path by apredetermined offset (e.g., a smart lane offset), if any (an offset ofzero may correspond to travel in the middle of a lane). The offset maybe in a direction perpendicular to a segment between any two points inthe vehicle path. In another embodiment, processing unit 110 may use onepolynomial and an estimated lane width to offset each point of thevehicle path by half the estimated lane width plus a predeterminedoffset (e.g., a smart lane offset).

At step 572, processing unit 110 may update the vehicle path constructedat step 570. Processing unit 110 may reconstruct the vehicle pathconstructed at step 570 using a higher resolution, such that thedistance d_(k) between two points in the set of points representing thevehicle path is less than the distance d_(i) described above. Forexample, the distance d_(k) may fall in the range of 0.1 to 0.3 meters.Processing unit 110 may reconstruct the vehicle path using a parabolicspline algorithm, which may yield a cumulative distance vector Scorresponding to the total length of the vehicle path (i.e., based onthe set of points representing the vehicle path).

At step 574, processing unit 110 may determine a look-ahead point(expressed in coordinates as (x_(l), z_(l))) based on the updatedvehicle path constructed at step 572. Processing unit 110 may extractthe look-ahead point from the cumulative distance vector S, and thelook-ahead point may be associated with a look-ahead distance andlook-ahead time. The look-ahead distance, which may have a lower boundranging from 10 to 20 meters, may be calculated as the product of thespeed of vehicle 200 and the look-ahead time. For example, as the speedof vehicle 200 decreases, the look-ahead distance may also decrease(e.g., until it reaches the lower bound). The look-ahead time, which mayrange from 0.5 to 1.5 seconds, may be inversely proportional to the gainof one or more control loops associated with causing a navigationalresponse in vehicle 200, such as the heading error tracking controlloop. For example, the gain of the heading error tracking control loopmay depend on the bandwidth of a yaw rate loop, a steering actuatorloop, car lateral dynamics, and the like. Thus, the higher the gain ofthe heading error tracking control loop, the lower the look-ahead time.

At step 576, processing unit 110 may determine a heading error and yawrate command based on the look-ahead point determined at step 574.Processing unit 110 may determine the heading error by calculating thearctangent of the look-ahead point, e.g., arctan (x_(l)/z_(l)).Processing unit 110 may determine the yaw rate command as the product ofthe heading error and a high-level control gain. The high-level controlgain may be equal to: (2/look-ahead time), if the look-ahead distance isnot at the lower bound. Otherwise, the high-level control gain may beequal to: (2*speed of vehicle 200/look-ahead distance).

FIG. 5F is a flowchart showing an exemplary process 500F for determiningwhether a leading vehicle is changing lanes, consistent with thedisclosed embodiments. At step 580, processing unit 110 may determinenavigation information associated with a leading vehicle (e.g., avehicle traveling ahead of vehicle 200). For example, processing unit110 may determine the position, velocity (e.g., direction and speed),and/or acceleration of the leading vehicle, using the techniquesdescribed in connection with FIGS. 5A and 5B, above. Processing unit 110may also determine one or more road polynomials, a look-ahead point(associated with vehicle 200), and/or a snail trail (e.g., a set ofpoints describing a path taken by the leading vehicle), using thetechniques described in connection with FIG. 5E, above.

At step 582, processing unit 110 may analyze the navigation informationdetermined at step 580. In one embodiment, processing unit 110 maycalculate the distance between a snail trail and a road polynomial(e.g., along the trail). If the variance of this distance along thetrail exceeds a predetermined threshold (for example, 0.1 to 0.2 meterson a straight road, 0.3 to 0.4 meters on a moderately curvy road, and0.5 to 0.6 meters on a road with sharp curves), processing unit 110 maydetermine that the leading vehicle is likely changing lanes. In the casewhere multiple vehicles are detected traveling ahead of vehicle 200,processing unit 110 may compare the snail trails associated with eachvehicle. Based on the comparison, processing unit 110 may determine thata vehicle whose snail trail does not match with the snail trails of theother vehicles is likely changing lanes. Processing unit 110 mayadditionally compare the curvature of the snail trail (associated withthe leading vehicle) with the expected curvature of the road segment inwhich the leading vehicle is traveling. The expected curvature may beextracted from map data (e.g., data from map database 160), from roadpolynomials, from other vehicles' snail trails, from prior knowledgeabout the road, and the like. If the difference in curvature of thesnail trail and the expected curvature of the road segment exceeds apredetermined threshold, processing unit 110 may determine that theleading vehicle is likely changing lanes.

In another embodiment, processing unit 110 may compare the leadingvehicle's instantaneous position with the look-ahead point (associatedwith vehicle 200) over a specific period of time (e.g., 0.5 to 1.5seconds). If the distance between the leading vehicle's instantaneousposition and the look-ahead point varies during the specific period oftime, and the cumulative sum of variation exceeds a predeterminedthreshold (for example, 0.3 to 0.4 meters on a straight road, 0.7 to 0.8meters on a moderately curvy road, and 1.3 to 1.7 meters on a road withsharp curves), processing unit 110 may determine that the leadingvehicle is likely changing lanes. In another embodiment, processing unit110 may analyze the geometry of the snail trail by comparing the lateraldistance traveled along the trail with the expected curvature of thesnail trail. The expected radius of curvature may be determinedaccording to the calculation: (δ_(z) ²+δ_(x) ²)/2/(δ_(x)), where δ_(x)represents the lateral distance traveled and δz represents thelongitudinal distance traveled. If the difference between the lateraldistance traveled and the expected curvature exceeds a predeterminedthreshold (e.g., 500 to 700 meters), processing unit 110 may determinethat the leading vehicle is likely changing lanes. In anotherembodiment, processing unit 110 may analyze the position of the leadingvehicle. If the position of the leading vehicle obscures a roadpolynomial (e.g., the leading vehicle is overlaid on top of the roadpolynomial), then processing unit 110 may determine that the leadingvehicle is likely changing lanes. In the case where the position of theleading vehicle is such that, another vehicle is detected ahead of theleading vehicle and the snail trails of the two vehicles are notparallel, processing unit 110 may determine that the (closer) leadingvehicle is likely changing lanes.

At step 584, processing unit 110 may determine whether or not leadingvehicle 200 is changing lanes based on the analysis performed at step582. For example, processing unit 110 may make the determination basedon a weighted average of the individual analyses performed at step 582.Under such a scheme, for example, a decision by processing unit 110 thatthe leading vehicle is likely changing lanes based on a particular typeof analysis may be assigned a value of “1” (and “0” to represent adetermination that the leading vehicle is not likely changing lanes).Different analyses performed at step 582 may be assigned differentweights, and the disclosed embodiments are not limited to any particularcombination of analyses and weights.

FIG. 6 is a flowchart showing an exemplary process 600 for causing oneor more navigational responses based on stereo image analysis,consistent with disclosed embodiments. At step 610, processing unit 110may receive a first and second plurality of images via data interface128. For example, cameras included in image acquisition unit 120 (suchas image capture devices 122 and 124 having fields of view 202 and 204)may capture a first and second plurality of images of an area forward ofvehicle 200 and transmit them over a digital connection (e.g., USB,wireless, Bluetooth, etc.) to processing unit 110. In some embodiments,processing unit 110 may receive the first and second plurality of imagesvia two or more data interfaces. The disclosed embodiments are notlimited to any particular data interface configurations or protocols.

At step 620, processing unit 110 may execute stereo image analysismodule 404 to perform stereo image analysis of the first and secondplurality of images to create a 3D map of the road in front of thevehicle and detect features within the images, such as lane markings,vehicles, pedestrians, road signs, highway exit ramps, traffic lights,road hazards, and the like. Stereo image analysis may be performed in amanner similar to the steps described in connection with FIGS. 5A-5D,above. For example, processing unit 110 may execute stereo imageanalysis module 404 to detect candidate objects (e.g., vehicles,pedestrians, road marks, traffic lights, road hazards, etc.) within thefirst and second plurality of images, filter out a subset of thecandidate objects based on various criteria, and perform multi-frameanalysis, construct measurements, and determine a confidence level forthe remaining candidate objects. In performing the steps above,processing unit 110 may consider information from both the first andsecond plurality of images, rather than information from one set ofimages alone. For example, processing unit 110 may analyze thedifferences in pixel-level data (or other data subsets from among thetwo streams of captured images) for a candidate object appearing in boththe first and second plurality of images. As another example, processingunit 110 may estimate a position and/or velocity of a candidate object(e.g., relative to vehicle 200) by observing that the object appears inone of the plurality of images but not the other or relative to otherdifferences that may exist relative to objects appearing if the twoimage streams. For example, position, velocity, and/or accelerationrelative to vehicle 200 may be determined based on trajectories,positions, movement characteristics, etc. of features associated with anobject appearing in one or both of the image streams.

At step 630, processing unit 110 may execute navigational responsemodule 408 to cause one or more navigational responses in vehicle 200based on the analysis performed at step 620 and the techniques asdescribed above in connection with FIG. 4 . Navigational responses mayinclude, for example, a turn, a lane shift, a change in acceleration, achange in velocity, braking, and the like. In some embodiments,processing unit 110 may use data derived from execution of velocity andacceleration module 406 to cause the one or more navigational responses.Additionally, multiple navigational responses may occur simultaneously,in sequence, or any combination thereof.

FIG. 7 is a flowchart showing an exemplary process 700 for causing oneor more navigational responses based on an analysis of three sets ofimages, consistent with disclosed embodiments. At step 710, processingunit 110 may receive a first, second, and third plurality of images viadata interface 128. For instance, cameras included in image acquisitionunit 120 (such as image capture devices 122, 124, and 126 having fieldsof view 202, 204, and 206) may capture a first, second, and thirdplurality of images of an area forward and/or to the side of vehicle 200and transmit them over a digital connection (e.g., USB, wireless,Bluetooth, etc.) to processing unit 110. In some embodiments, processingunit 110 may receive the first, second, and third plurality of imagesvia three or more data interfaces. For example, each of image capturedevices 122, 124, 126 may have an associated data interface forcommunicating data to processing unit 110. The disclosed embodiments arenot limited to any particular data interface configurations orprotocols.

At step 720, processing unit 110 may analyze the first, second, andthird plurality of images to detect features within the images, such aslane markings, vehicles, pedestrians, road signs, highway exit ramps,traffic lights, road hazards, and the like. The analysis may beperformed in a manner similar to the steps described in connection withFIGS. 5A-5D and 6 , above. For instance, processing unit 110 may performmonocular image analysis (e.g., via execution of monocular imageanalysis module 402 and based on the steps described in connection withFIGS. 5A-5D, above) on each of the first, second, and third plurality ofimages. Alternatively, processing unit 110 may perform stereo imageanalysis (e.g., via execution of stereo image analysis module 404 andbased on the steps described in connection with FIG. 6 , above) on thefirst and second plurality of images, the second and third plurality ofimages, and/or the first and third plurality of images. The processedinformation corresponding to the analysis of the first, second, and/orthird plurality of images may be combined. In some embodiments,processing unit 110 may perform a combination of monocular and stereoimage analyses. For example, processing unit 110 may perform monocularimage analysis (e.g., via execution of monocular image analysis module402) on the first plurality of images and stereo image analysis (e.g.,via execution of stereo image analysis module 404) on the second andthird plurality of images. The configuration of image capture devices122, 124, and 126—including their respective locations and fields ofview 202, 204, and 206—may influence the types of analyses conducted onthe first, second, and third plurality of images. The disclosedembodiments are not limited to a particular configuration of imagecapture devices 122, 124, and 126, or the types of analyses conducted onthe first, second, and third plurality of images.

In some embodiments, processing unit 110 may perform testing on system100 based on the images acquired and analyzed at steps 710 and 720. Suchtesting may provide an indicator of the overall performance of system100 for certain configurations of image capture devices 122, 124, and126. For example, processing unit 110 may determine the proportion of“false hits” (e.g., cases where system 100 incorrectly determined thepresence of a vehicle or pedestrian) and “misses.”

At step 730, processing unit 110 may cause one or more navigationalresponses in vehicle 200 based on information derived from two of thefirst, second, and third plurality of images. Selection of two of thefirst, second, and third plurality of images may depend on variousfactors, such as, for example, the number, types, and sizes of objectsdetected in each of the plurality of images. Processing unit 110 mayalso make the selection based on image quality and resolution, theeffective field of view reflected in the images, the number of capturedframes, the extent to which one or more objects of interest actuallyappear in the frames (e.g., the percentage of frames in which an objectappears, the proportion of the object that appears in each such frame,etc.), and the like.

In some embodiments, processing unit 110 may select information derivedfrom two of the first, second, and third plurality of images bydetermining the extent to which information derived from one imagesource is consistent with information derived from other image sources.For example, processing unit 110 may combine the processed informationderived from each of image capture devices 122, 124, and 126 (whether bymonocular analysis, stereo analysis, or any combination of the two) anddetermine visual indicators (e.g., lane markings, a detected vehicle andits location and/or path, a detected traffic light, etc.) that areconsistent across the images captured from each of image capture devices122, 124, and 126. Processing unit 110 may also exclude information thatis inconsistent across the captured images (e.g., a vehicle changinglanes, a lane model indicating a vehicle that is too close to vehicle200, etc.). Thus, processing unit 110 may select information derivedfrom two of the first, second, and third plurality of images based onthe determinations of consistent and inconsistent information.

Navigational responses may include, for example, a turn, a lane shift, achange in acceleration, and the like. Processing unit 110 may cause theone or more navigational responses based on the analysis performed atstep 720 and the techniques as described above in connection with FIG. 4. Processing unit 110 may also use data derived from execution ofvelocity and acceleration module 406 to cause the one or morenavigational responses. In some embodiments, processing unit 110 maycause the one or more navigational responses based on a relativeposition, relative velocity, and/or relative acceleration betweenvehicle 200 and an object detected within any of the first, second, andthird plurality of images. Multiple navigational responses may occursimultaneously, in sequence, or any combination thereof

Sparse Road Model for Autonomous Vehicle Navigation

In some embodiments, the disclosed systems and methods may use a sparsemap for autonomous vehicle navigation. In particular, the sparse map maybe for autonomous vehicle navigation along a road segment. For example,the sparse map may provide sufficient information for navigating anautonomous vehicle without storing and/or updating a large quantity ofdata. As discussed below in further detail, an autonomous vehicle mayuse the sparse map to navigate one or more roads based on one or morestored trajectories.

Sparse Map for Autonomous Vehicle Navigation

In some embodiments, the disclosed systems and methods may generate asparse map for autonomous vehicle navigation. For example, the sparsemap may provide sufficient information for navigation without requiringexcessive data storage or data transfer rates. As discussed below infurther detail, a vehicle (which may be an autonomous vehicle) may usethe sparse map to navigate one or more roads. For example, in someembodiments, the sparse map may include data related to a road andpotentially landmarks along the road that may be sufficient for vehiclenavigation, but which also exhibit small data footprints. For example,the sparse data maps described in detail below may require significantlyless storage space and data transfer bandwidth as compared with digitalmaps including detailed map information, such as image data collectedalong a road.

For example, rather than storing detailed representations of a roadsegment, the sparse data map may store three-dimensional polynomialrepresentations of preferred vehicle paths along a road. These paths mayrequire very little data storage space. Further, in the described sparsedata maps, landmarks may be identified and included in the sparse maproad model to aid in navigation. These landmarks may be located at anyspacing suitable for enabling vehicle navigation, but in some cases,such landmarks need not be identified and included in the model at highdensities and short spacings. Rather, in some cases, navigation may bepossible based on landmarks that are spaced apart by at least 50 meters,at least 100 meters, at least 500 meters, at least 1 kilometer, or atleast 2 kilometers. As will be discussed in more detail in othersections, the sparse map may be generated based on data collected ormeasured by vehicles equipped with various sensors and devices, such asimage capture devices, Global Positioning System sensors, motionsensors, etc., as the vehicles travel along roadways. In some cases, thesparse map may be generated based on data collected during multipledrives of one or more vehicles along a particular roadway. Generating asparse map using multiple drives of one or more vehicles may be referredto as “crowdsourcing” a sparse map.

Consistent with disclosed embodiments, an autonomous vehicle system mayuse a sparse map for navigation. For example, the disclosed systems andmethods may distribute a sparse map for generating a road navigationmodel for an autonomous vehicle and may navigate an autonomous vehiclealong a road segment using a sparse map and/or a generated roadnavigation model. Sparse maps consistent with the present disclosure mayinclude one or more three-dimensional contours that may representpredetermined trajectories that autonomous vehicles may traverse as theymove along associated road segments.

Sparse maps consistent with the present disclosure may also include datarepresenting one or more road features. Such road features may includerecognized landmarks, road signature profiles, and any otherroad-related features useful in navigating a vehicle. Sparse mapsconsistent with the present disclosure may enable autonomous navigationof a vehicle based on relatively small amounts of data included in thesparse map. For example, rather than including detailed representationsof a road, such as road edges, road curvature, images associated withroad segments, or data detailing other physical features associated witha road segment, the disclosed embodiments of the sparse map may requirerelatively little storage space (and relatively little bandwidth whenportions of the sparse map are transferred to a vehicle) but may stilladequately provide for autonomous vehicle navigation. The small datafootprint of the disclosed sparse maps, discussed in further detailbelow, may be achieved in some embodiments by storing representations ofroad-related elements that require small amounts of data but stillenable autonomous navigation.

For example, rather than storing detailed representations of variousaspects of a road, the disclosed sparse maps may store polynomialrepresentations of one or more trajectories that a vehicle may followalong the road. Thus, rather than storing (or having to transfer)details regarding the physical nature of the road to enable navigationalong the road, using the disclosed sparse maps, a vehicle may benavigated along a particular road segment without, in some cases, havingto interpret physical aspects of the road, but rather, by aligning itspath of travel with a trajectory (e.g., a polynomial spline) along theparticular road segment. In this way, the vehicle may be navigated basedmainly upon the stored trajectory (e.g., a polynomial spline) that mayrequire much less storage space than an approach involving storage ofroadway images, road parameters, road layout, etc.

In addition to the stored polynomial representations of trajectoriesalong a road segment, the disclosed sparse maps may also include smalldata objects that may represent a road feature. In some embodiments, thesmall data objects may include digital signatures, which are derivedfrom a digital image (or a digital signal) that was obtained by a sensor(e.g., a camera or other sensor, such as a suspension sensor) onboard avehicle traveling along the road segment. The digital signature may havea reduced size relative to the signal that was acquired by the sensor.In some embodiments, the digital signature may be created to becompatible with a classifier function that is configured to detect andto identify the road feature from the signal that is acquired by thesensor, for example, during a subsequent drive. In some embodiments, adigital signature may be created such that the digital signature has afootprint that is as small as possible, while retaining the ability tocorrelate or match the road feature with the stored signature based onan image (or a digital signal generated by a sensor, if the storedsignature is not based on an image and/or includes other data) of theroad feature that is captured by a camera onboard a vehicle travelingalong the same road segment at a subsequent time.

In some embodiments, a size of the data objects may be furtherassociated with a uniqueness of the road feature. For example, for aroad feature that is detectable by a camera onboard a vehicle, and wherethe camera system onboard the vehicle is coupled to a classifier that iscapable of distinguishing the image data corresponding to that roadfeature as being associated with a particular type of road feature, forexample, a road sign, and where such a road sign is locally unique inthat area (e.g., there is no identical road sign or road sign of thesame type nearby), it may be sufficient to store data indicating thetype of the road feature and its location.

As will be discussed in further detail below, road features (e.g.,landmarks along a road segment) may be stored as small data objects thatmay represent a road feature in relatively few bytes, while at the sametime providing sufficient information for recognizing and using such afeature for navigation. In one example, a road sign may be identified asa recognized landmark on which navigation of a vehicle may be based. Arepresentation of the road sign may be stored in the sparse map toinclude, e.g., a few bytes of data indicating a type of landmark (e.g.,a stop sign) and a few bytes of data indicating a location of thelandmark (e.g., coordinates). Navigating based on such data-lightrepresentations of the landmarks (e.g., using representations sufficientfor locating, recognizing, and navigating based upon the landmarks) mayprovide a desired level of navigational functionality associated withsparse maps without significantly increasing the data overheadassociated with the sparse maps. This lean representation of landmarks(and other road features) may take advantage of the sensors andprocessors included onboard such vehicles that are configured to detect,identify, and/or classify certain road features.

When, for example, a sign or even a particular type of a sign is locallyunique (e.g., when there is no other sign or no other sign of the sametype) in a given area, the sparse map may use data indicating a type ofa landmark (a sign or a specific type of sign), and during navigation(e.g., autonomous navigation) when a camera onboard an autonomousvehicle captures an image of the area including a sign (or of a specifictype of sign), the processor may process the image, detect the sign (ifindeed present in the image), classify the image as a sign (or as aspecific type of sign), and correlate the location of the image with thelocation of the sign as stored in the sparse map.

The sparse map may include any suitable representation of objectsidentified along a road segment. In some cases, the objects may bereferred to as semantic objects or non-semantic objects. Semanticobjects may include, for example, objects associated with apredetermined type classification. This type classification may beuseful in reducing the amount of data required to describe the semanticobject recognized in an environment, which can be beneficial both in theharvesting phase (e.g., to reduce costs associated with bandwidth usefor transferring drive information from a plurality of harvestingvehicles to a server) and during the navigation phase (e.g., reductionof map data can speed transfer of map tiles from a server to anavigating vehicle and can also reduce costs associated with bandwidthuse for such transfers). Semantic object classification types may beassigned to any type of objects or features that are expected to beencountered along a roadway.

Semantic objects may further be divided into two or more logical groups.For example, in some cases, one group of semantic object types may beassociated with predetermined dimensions. Such semantic objects mayinclude certain speed limit signs, yield signs, merge signs, stop signs,traffic lights, directional arrows on a roadway, manhole covers, or anyother type of object that may be associated with a standardized size.One benefit offered by such semantic objects is that very little datamay be needed to represent/fully define the objects. For example, if astandardized size of a speed limit size is known, then a harvestingvehicle may need only identify (through analysis of a captured image)the presence of a speed limit sign (a recognized type) along with anindication of a position of the detected speed limit sign (e.g., a 2Dposition in the captured image (or, alternatively, a 3D position in realworld coordinates) of a center of the sign or a certain corner of thesign) to provide sufficient information for map generation on the serverside. Where 2D image positions are transmitted to the server, a positionassociated with the captured image where the sign was detected may alsobe transmitted so the server can determine a real-world position of thesign (e.g., through structure in motion techniques using multiplecaptured images from one or more harvesting vehicles). Even with thislimited information (requiring just a few bytes to define each detectedobject), the server may construct the map including a fully representedspeed limit sign based on the type classification (representative of aspeed limit sign) received from one or more harvesting vehicles alongwith the position information for the detected sign.

Semantic objects may also include other recognized object or featuretypes that are not associated with certain standardized characteristics.Such objects or features may include potholes, tar seams, light poles,non-standardized signs, curbs, trees, tree branches, or any other typeof recognized object type with one or more variable characteristics(e.g., variable dimensions). In such cases, in addition to transmittingto a server an indication of the detected object or feature type (e.g.,pothole, pole, etc.) and position information for the detected object orfeature, a harvesting vehicle may also transmit an indication of a sizeof the object or feature. The size may be expressed in 2D imagedimensions (e.g., with a bounding box or one or more dimension values)or real-world dimensions (determined through structure in motioncalculations, based on LIDAR or RADAR system outputs, based on trainedneural network outputs, etc.).

Non-semantic objects or features may include any detectable objects orfeatures that fall outside of a recognized category or type, but thatstill may provide valuable information in map generation. In some cases,such non-semantic features may include a detected corner of a buildingor a corner of a detected window of a building, a unique stone or objectnear a roadway, a concrete splatter in a roadway shoulder, or any otherdetectable object or feature. Upon detecting such an object or featureone or more harvesting vehicles may transmit to a map generation servera location of one or more points (2D image points or 3D real worldpoints) associated with the detected object/feature. Additionally, acompressed or simplified image segment (e.g., an image hash) may begenerated for a region of the captured image including the detectedobject or feature. This image hash may be calculated based on apredetermined image processing algorithm and may form an effectivesignature for the detected non-semantic object or feature. Such asignature may be useful for navigation relative to a sparse mapincluding the non-semantic feature or object, as a vehicle traversingthe roadway may apply an algorithm similar to the algorithm used togenerate the image hash in order to confirm/verify the presence in acaptured image of the mapped non-semantic feature or object. Using thistechnique, non-semantic features may add to the richness of the sparsemaps (e.g., to enhance their usefulness in navigation) without addingsignificant data overhead.

As noted, target trajectories may be stored in the sparse map. Thesetarget trajectories (e.g., 3D splines) may represent the preferred orrecommended paths for each available lane of a roadway, each validpathway through a junction, for merges and exits, etc. In addition totarget trajectories, other road feature may also be detected, harvested,and incorporated in the sparse maps in the form of representativesplines. Such features may include, for example, road edges, lanemarkings, curbs, guardrails, or any other objects or features thatextend along a roadway or road segment.

Generating a Sparse Map

In some embodiments, a sparse map may include at least one linerepresentation of a road surface feature extending along a road segmentand a plurality of landmarks associated with the road segment. Incertain aspects, the sparse map may be generated via “crowdsourcing,”for example, through image analysis of a plurality of images acquired asone or more vehicles traverse the road segment.

FIG. 8 shows a sparse map 800 that one or more vehicles, e.g., vehicle200 (which may be an autonomous vehicle), may access for providingautonomous vehicle navigation. Sparse map 800 may be stored in a memory,such as memory 140 or 150. Such memory devices may include any types ofnon-transitory storage devices or computer-readable media. For example,in some embodiments, memory 140 or 150 may include hard drives, compactdiscs, flash memory, magnetic based memory devices, optical based memorydevices, etc. In some embodiments, sparse map 800 may be stored in adatabase (e.g., map database 160) that may be stored in memory 140 or150, or other types of storage devices.

In some embodiments, sparse map 800 may be stored on a storage device ora non-transitory computer-readable medium provided onboard vehicle 200(e.g., a storage device included in a navigation system onboard vehicle200). A processor (e.g., processing unit 110) provided on vehicle 200may access sparse map 800 stored in the storage device orcomputer-readable medium provided onboard vehicle 200 in order togenerate navigational instructions for guiding the autonomous vehicle200 as the vehicle traverses a road segment.

Sparse map 800 need not be stored locally with respect to a vehicle,however. In some embodiments, sparse map 800 may be stored on a storagedevice or computer-readable medium provided on a remote server thatcommunicates with vehicle 200 or a device associated with vehicle 200. Aprocessor (e.g., processing unit 110) provided on vehicle 200 mayreceive data included in sparse map 800 from the remote server and mayexecute the data for guiding the autonomous driving of vehicle 200. Insuch embodiments, the remote server may store all of sparse map 800 oronly a portion thereof. Accordingly, the storage device orcomputer-readable medium provided onboard vehicle 200 and/or onboard oneor more additional vehicles may store the remaining portion(s) of sparsemap 800.

Furthermore, in such embodiments, sparse map 800 may be made accessibleto a plurality of vehicles traversing various road segments (e.g., tens,hundreds, thousands, or millions of vehicles, etc.). It should be notedalso that sparse map 800 may include multiple sub-maps. For example, insome embodiments, sparse map 800 may include hundreds, thousands,millions, or more, of sub-maps (e.g., map tiles) that may be used innavigating a vehicle. Such sub-maps may be referred to as local maps ormap tiles, and a vehicle traveling along a roadway may access any numberof local maps relevant to a location in which the vehicle is traveling.The local map sections of sparse map 800 may be stored with a GlobalNavigation Satellite System (GNSS) key as an index to the database ofsparse map 800. Thus, while computation of steering angles fornavigating a host vehicle in the present system may be performed withoutreliance upon a GNSS position of the host vehicle, road features, orlandmarks, such GNSS information may be used for retrieval of relevantlocal maps.

In general, sparse map 800 may be generated based on data (e.g., driveinformation) collected from one or more vehicles as they travel alongroadways. For example, using sensors aboard the one or more vehicles(e.g., cameras, speedometers, GPS, accelerometers, etc.), thetrajectories that the one or more vehicles travel along a roadway may berecorded, and the polynomial representation of a preferred trajectoryfor vehicles making subsequent trips along the roadway may be determinedbased on the collected trajectories travelled by the one or morevehicles. Similarly, data collected by the one or more vehicles may aidin identifying potential landmarks along a particular roadway. Datacollected from traversing vehicles may also be used to identify roadprofile information, such as road width profiles, road roughnessprofiles, traffic line spacing profiles, road conditions, etc. Using thecollected information, sparse map 800 may be generated and distributed(e.g., for local storage or via on-the-fly data transmission) for use innavigating one or more autonomous vehicles. However, in someembodiments, map generation may not end upon initial generation of themap. As will be discussed in greater detail below, sparse map 800 may becontinuously or periodically updated based on data collected fromvehicles as those vehicles continue to traverse roadways included insparse map 800.

Data recorded in sparse map 800 may include position information basedon Global Positioning System (GPS) data. For example, locationinformation may be included in sparse map 800 for various map elements,including, for example, landmark locations, road profile locations, etc.Locations for map elements included in sparse map 800 may be obtainedusing GPS data collected from vehicles traversing a roadway. Forexample, a vehicle passing an identified landmark may determine alocation of the identified landmark using GPS position informationassociated with the vehicle and a determination of a location of theidentified landmark relative to the vehicle (e.g., based on imageanalysis of data collected from one or more cameras on board thevehicle). Such location determinations of an identified landmark (or anyother feature included in sparse map 800) may be repeated as additionalvehicles pass the location of the identified landmark. Some or all ofthe additional location determinations may be used to refine thelocation information stored in sparse map 800 relative to the identifiedlandmark. For example, in some embodiments, multiple positionmeasurements relative to a particular feature stored in sparse map 800may be averaged together. Any other mathematical operations, however,may also be used to refine a stored location of a map element based on aplurality of determined locations for the map element.

In a particular example, harvesting vehicles may traverse a particularroad segment. Each harvesting vehicle captures images of theirrespective environments. The images may be collected at any suitableframe capture rate (e.g., 9 Hz, etc.). Image analysis processor(s)aboard each harvesting vehicle analyze the captured images to detect thepresence of semantic and/or non-semantic features/objects. At a highlevel, the harvesting vehicles transmit to a mapping-server indicationsof detections of the semantic and/or non-semantic objects/features alongwith positions associated with those objects/features. In more detail,type indicators, dimension indicators, etc. may be transmitted togetherwith the position information. The position information may include anysuitable information for enabling the mapping server to aggregate thedetected objects/features into a sparse map useful in navigation. Insome cases, the position information may include one or more 2D imagepositions (e.g., X-Y pixel locations) in a captured image where thesemantic or non-semantic features/objects were detected. Such imagepositions may correspond to a center of the feature/object, a corner,etc. In this scenario, to aid the mapping server in reconstructing thedrive information and aligning the drive information from multipleharvesting vehicles, each harvesting vehicle may also provide the serverwith a location (e.g., a GPS location) where each image was captured.

In other cases, the harvesting vehicle may provide to the server one ormore 3D real world points associated with the detected objects/features.Such 3D points may be relative to a predetermined origin (such as anorigin of a drive segment) and may be determined through any suitabletechnique. In some cases, a structure in motion technique may be used todetermine the 3D real world position of a detected object/feature. Forexample, a certain object such as a particular speed limit sign may bedetected in two or more captured images. Using information such as theknown ego motion (speed, trajectory, GPS position, etc.) of theharvesting vehicle between the captured images, along with observedchanges of the speed limit sign in the captured images (change in X-Ypixel location, change in size, etc.), the real-world position of one ormore points associated with the speed limit sign may be determined andpassed along to the mapping server. Such an approach is optional, as itrequires more computation on the part of the harvesting vehicle systems.The sparse map of the disclosed embodiments may enable autonomousnavigation of a vehicle using relatively small amounts of stored data.In some embodiments, sparse map 800 may have a data density (e.g.,including data representing the target trajectories, landmarks, and anyother stored road features) of less than 2 MB per kilometer of roads,less than 1 MB per kilometer of roads, less than 500 kB per kilometer ofroads, or less than 100 kB per kilometer of roads. In some embodiments,the data density of sparse map 800 may be less than 10 kB per kilometerof roads or even less than 2 kB per kilometer of roads (e.g., 1.6 kB perkilometer), or no more than 10 kB per kilometer of roads, or no morethan 20 kB per kilometer of roads. In some embodiments, most, if notall, of the roadways of the United States may be navigated autonomouslyusing a sparse map having a total of 4 GB or less of data. These datadensity values may represent an average over an entire sparse map 800,over a local map within sparse map 800, and/or over a particular roadsegment within sparse map 800.

As noted, sparse map 800 may include representations of a plurality oftarget trajectories 810 for guiding autonomous driving or navigationalong a road segment. Such target trajectories may be stored asthree-dimensional splines. The target trajectories stored in sparse map800 may be determined based on two or more reconstructed trajectories ofprior traversals of vehicles along a particular road segment, forexample. A road segment may be associated with a single targettrajectory or multiple target trajectories. For example, on a two laneroad, a first target trajectory may be stored to represent an intendedpath of travel along the road in a first direction, and a second targettrajectory may be stored to represent an intended path of travel alongthe road in another direction (e.g., opposite to the first direction).Additional target trajectories may be stored with respect to aparticular road segment. For example, on a multi-lane road one or moretarget trajectories may be stored representing intended paths of travelfor vehicles in one or more lanes associated with the multi-lane road.In some embodiments, each lane of a multi-lane road may be associatedwith its own target trajectory. In other embodiments, there may be fewertarget trajectories stored than lanes present on a multi-lane road. Insuch cases, a vehicle navigating the multi-lane road may use any of thestored target trajectories to guides its navigation by taking intoaccount an amount of lane offset from a lane for which a targettrajectory is stored (e.g., if a vehicle is traveling in the left mostlane of a three lane highway, and a target trajectory is stored only forthe middle lane of the highway, the vehicle may navigate using thetarget trajectory of the middle lane by accounting for the amount oflane offset between the middle lane and the left-most lane whengenerating navigational instructions).

In some embodiments, the target trajectory may represent an ideal paththat a vehicle should take as the vehicle travels. The target trajectorymay be located, for example, at an approximate center of a lane oftravel. In other cases, the target trajectory may be located elsewhererelative to a road segment. For example, a target trajectory mayapproximately coincide with a center of a road, an edge of a road, or anedge of a lane, etc. In such cases, navigation based on the targettrajectory may include a determined amount of offset to be maintainedrelative to the location of the target trajectory. Moreover, in someembodiments, the determined amount of offset to be maintained relativeto the location of the target trajectory may differ based on a type ofvehicle (e.g., a passenger vehicle including two axles may have adifferent offset from a truck including more than two axles along atleast a portion of the target trajectory).

Sparse map 800 may also include data relating to a plurality ofpredetermined landmarks 820 associated with particular road segments,local maps, etc. As discussed in greater detail below, these landmarksmay be used in navigation of the autonomous vehicle. For example, insome embodiments, the landmarks may be used to determine a currentposition of the vehicle relative to a stored target trajectory. Withthis position information, the autonomous vehicle may be able to adjusta heading direction to match a direction of the target trajectory at thedetermined location.

The plurality of landmarks 820 may be identified and stored in sparsemap 800 at any suitable spacing. In some embodiments, landmarks may bestored at relatively high densities (e.g., every few meters or more). Insome embodiments, however, significantly larger landmark spacing valuesmay be employed. For example, in sparse map 800, identified (orrecognized) landmarks may be spaced apart by 10 meters, 20 meters, 50meters, 100 meters, 1 kilometer, or 2 kilometers. In some cases, theidentified landmarks may be located at distances of even more than 2kilometers apart.

Between landmarks, and therefore between determinations of vehicleposition relative to a target trajectory, the vehicle may navigate basedon dead reckoning in which the vehicle uses sensors to determine its egomotion and estimate its position relative to the target trajectory.Because errors may accumulate during navigation by dead reckoning, overtime the position determinations relative to the target trajectory maybecome increasingly less accurate. The vehicle may use landmarksoccurring in sparse map 800 (and their known locations) to remove thedead reckoning-induced errors in position determination. In this way,the identified landmarks included in sparse map 800 may serve asnavigational anchors from which an accurate position of the vehiclerelative to a target trajectory may be determined. Because a certainamount of error may be acceptable in position location, an identifiedlandmark need not always be available to an autonomous vehicle. Rather,suitable navigation may be possible even based on landmark spacings, asnoted above, of 10 meters, 20 meters, 50 meters, 100 meters, 500 meters,1 kilometer, 2 kilometers, or more. In some embodiments, a density of 1identified landmark every 1 km of road may be sufficient to maintain alongitudinal position determination accuracy within 1 m. Thus, not everypotential landmark appearing along a road segment need be stored insparse map 800.

Moreover, in some embodiments, lane markings may be used forlocalization of the vehicle during landmark spacings. By using lanemarkings during landmark spacings, the accumulation of errors duringnavigation by dead reckoning may be minimized.

In addition to target trajectories and identified landmarks, sparse map800 may include information relating to various other road features. Forexample, FIG. 9A illustrates a representation of curves along aparticular road segment that may be stored in sparse map 800. In someembodiments, a single lane of a road may be modeled by athree-dimensional polynomial description of left and right sides of theroad. Such polynomials representing left and right sides of a singlelane are shown in FIG. 9A. Regardless of how many lanes a road may have,the road may be represented using polynomials in a way similar to thatillustrated in FIG. 9A. For example, left and right sides of amulti-lane road may be represented by polynomials similar to those shownin FIG. 9A, and intermediate lane markings included on a multi-lane road(e.g., dashed markings representing lane boundaries, solid yellow linesrepresenting boundaries between lanes traveling in different directions,etc.) may also be represented using polynomials such as those shown inFIG. 9A.

As shown in FIG. 9A, a lane 900 may be represented using polynomials(e.g., a first order, second order, third order, or any suitable orderpolynomials). For illustration, lane 900 is shown as a two-dimensionallane and the polynomials are shown as two-dimensional polynomials. Asdepicted in FIG. 9A, lane 900 includes a left side 910 and a right side920. In some embodiments, more than one polynomial may be used torepresent a location of each side of the road or lane boundary. Forexample, each of left side 910 and right side 920 may be represented bya plurality of polynomials of any suitable length. In some cases, thepolynomials may have a length of about 100 m, although other lengthsgreater than or less than 100 m may also be used. Additionally, thepolynomials can overlap with one another in order to facilitate seamlesstransitions in navigating based on subsequently encountered polynomialsas a host vehicle travels along a roadway. For example, each of leftside 910 and right side 920 may be represented by a plurality of thirdorder polynomials separated into segments of about 100 meters in length(an example of the first predetermined range), and overlapping eachother by about 50 meters. The polynomials representing the left side 910and the right side 920 may or may not have the same order. For example,in some embodiments, some polynomials may be second order polynomials,some may be third order polynomials, and some may be fourth orderpolynomials.

In the example shown in FIG. 9A, left side 910 of lane 900 isrepresented by two groups of third order polynomials. The first groupincludes polynomial segments 911, 912, and 913. The second groupincludes polynomial segments 914, 915, and 916. The two groups, whilesubstantially parallel to each other, follow the locations of theirrespective sides of the road. Polynomial segments 911, 912, 913, 914,915, and 916 have a length of about 100 meters and overlap adjacentsegments in the series by about 50 meters. As noted previously, however,polynomials of different lengths and different overlap amounts may alsobe used. For example, the polynomials may have lengths of 500 m, 1 km,or more, and the overlap amount may vary from 0 to 50 m, 50 m to 100 m,or greater than 100 m. Additionally, while FIG. 9A is shown asrepresenting polynomials extending in 2D space (e.g., on the surface ofthe paper), it is to be understood that these polynomials may representcurves extending in three dimensions (e.g., including a heightcomponent) to represent elevation changes in a road segment in additionto X-Y curvature. In the example shown in FIG. 9A, right side 920 oflane 900 is further represented by a first group having polynomialsegments 921, 922, and 923 and a second group having polynomial segments924, 925, and 926.

Returning to the target trajectories of sparse map 800, FIG. 9B shows athree-dimensional polynomial representing a target trajectory for avehicle traveling along a particular road segment. The target trajectoryrepresents not only the X-Y path that a host vehicle should travel alonga particular road segment, but also the elevation change that the hostvehicle will experience when traveling along the road segment. Thus,each target trajectory in sparse map 800 may be represented by one ormore three-dimensional polynomials, like the three-dimensionalpolynomial 950 shown in FIG. 9B. Sparse map 800 may include a pluralityof trajectories (e.g., millions or billions or more to representtrajectories of vehicles along various road segments along roadwaysthroughout the world). In some embodiments, each target trajectory maycorrespond to a spline connecting three-dimensional polynomial segments.

Regarding the data footprint of polynomial curves stored in sparse map800, in some embodiments, each third degree polynomial may berepresented by four parameters, each requiring four bytes of data.Suitable representations may be obtained with third degree polynomialsrequiring about 192 bytes of data for every 100 m. This may translate toapproximately 200 kB per hour in data usage/transfer requirements for ahost vehicle traveling approximately 100 km/hr.

Sparse map 800 may describe the lanes network using a combination ofgeometry descriptors and meta-data. The geometry may be described bypolynomials or splines as described above. The meta-data may describethe number of lanes, special characteristics (such as a car pool lane),and possibly other sparse labels. The total footprint of such indicatorsmay be negligible.

Accordingly, a sparse map according to embodiments of the presentdisclosure may include at least one line representation of a roadsurface feature extending along the road segment, each linerepresentation representing a path along the road segment substantiallycorresponding with the road surface feature. In some embodiments, asdiscussed above, the at least one line representation of the roadsurface feature may include a spline, a polynomial representation, or acurve. Furthermore, in some embodiments, the road surface feature mayinclude at least one of a road edge or a lane marking. Moreover, asdiscussed below with respect to “crowdsourcing,” the road surfacefeature may be identified through image analysis of a plurality ofimages acquired as one or more vehicles traverse the road segment.

As previously noted, sparse map 800 may include a plurality ofpredetermined landmarks associated with a road segment. Rather thanstoring actual images of the landmarks and relying, for example, onimage recognition analysis based on captured images and stored images,each landmark in sparse map 800 may be represented and recognized usingless data than a stored, actual image would require. Data representinglandmarks may still include sufficient information for describing oridentifying the landmarks along a road. Storing data describingcharacteristics of landmarks, rather than the actual images oflandmarks, may reduce the size of sparse map 800.

FIG. 10 illustrates examples of types of landmarks that may berepresented in sparse map 800. The landmarks may include any visible andidentifiable objects along a road segment. The landmarks may be selectedsuch that they are fixed and do not change often with respect to theirlocations and/or content. The landmarks included in sparse map 800 maybe useful in determining a location of vehicle 200 with respect to atarget trajectory as the vehicle traverses a particular road segment.Examples of landmarks may include traffic signs, directional signs,general signs (e.g., rectangular signs), roadside fixtures (e.g.,lampposts, reflectors, etc.), and any other suitable category. In someembodiments, lane marks on the road, may also be included as landmarksin sparse map 800.

Examples of landmarks shown in FIG. 10 include traffic signs,directional signs, roadside fixtures, and general signs. Traffic signsmay include, for example, speed limit signs (e.g., speed limit sign1000), yield signs (e.g., yield sign 1005), route number signs (e.g.,route number sign 1010), traffic light signs (e.g., traffic light sign1015), stop signs (e.g., stop sign 1020). Directional signs may includea sign that includes one or more arrows indicating one or moredirections to different places. For example, directional signs mayinclude a highway sign 1025 having arrows for directing vehicles todifferent roads or places, an exit sign 1030 having an arrow directingvehicles off a road, etc. Accordingly, at least one of the plurality oflandmarks may include a road sign.

General signs may be unrelated to traffic. For example, general signsmay include billboards used for advertisement, or a welcome boardadjacent a border between two countries, states, counties, cities, ortowns. FIG. 10 shows a general sign 1040 (“Joe's Restaurant”). Althoughgeneral sign 1040 may have a rectangular shape, as shown in FIG. 10 ,general sign 1040 may have other shapes, such as square, circle,triangle, etc.

Landmarks may also include roadside fixtures. Roadside fixtures may beobjects that are not signs, and may not be related to traffic ordirections. For example, roadside fixtures may include lampposts (e.g.,lamppost 1035), power line posts, traffic light posts, etc.

Landmarks may also include beacons that may be specifically designed forusage in an autonomous vehicle navigation system. For example, suchbeacons may include stand-alone structures placed at predeterminedintervals to aid in navigating a host vehicle. Such beacons may alsoinclude visual/graphical information added to existing road signs (e.g.,icons, emblems, bar codes, etc.) that may be identified or recognized bya vehicle traveling along a road segment. Such beacons may also includeelectronic components. In such embodiments, electronic beacons (e.g.,RFID tags, etc.) may be used to transmit non-visual information to ahost vehicle. Such information may include, for example, landmarkidentification and/or landmark location information that a host vehiclemay use in determining its position along a target trajectory.

In some embodiments, the landmarks included in sparse map 800 may berepresented by a data object of a predetermined size. The datarepresenting a landmark may include any suitable parameters foridentifying a particular landmark. For example, in some embodiments,landmarks stored in sparse map 800 may include parameters such as aphysical size of the landmark (e.g., to support estimation of distanceto the landmark based on a known size/scale), a distance to a previouslandmark, lateral offset, height, a type code (e.g., a landmarktype—what type of directional sign, traffic sign, etc.), a GPScoordinate (e.g., to support global localization), and any othersuitable parameters. Each parameter may be associated with a data size.For example, a landmark size may be stored using 8 bytes of data. Adistance to a previous landmark, a lateral offset, and height may bespecified using 12 bytes of data. A type code associated with a landmarksuch as a directional sign or a traffic sign may require about 2 bytesof data. For general signs, an image signature enabling identificationof the general sign may be stored using 50 bytes of data storage. Thelandmark GPS position may be associated with 16 bytes of data storage.These data sizes for each parameter are examples only, and other datasizes may also be used. Representing landmarks in sparse map 800 in thismanner may offer a lean solution for efficiently representing landmarksin the database. In some embodiments, objects may be referred to asstandard semantic objects or non-standard semantic objects. A standardsemantic object may include any class of object for which there's astandardized set of characteristics (e.g., speed limit signs, warningsigns, directional signs, traffic lights, etc. having known dimensionsor other characteristics). A non-standard semantic object may includeany object that is not associated with a standardized set ofcharacteristics (e.g., general advertising signs, signs identifyingbusiness establishments, potholes, trees, etc. that may have variabledimensions). Each non-standard semantic object may be represented with38 bytes of data (e.g., 8 bytes for size; 12 bytes for distance toprevious landmark, lateral offset, and height; 2 bytes for a type code;and 16 bytes for position coordinates). Standard semantic objects may berepresented using even less data, as size information may not be neededby the mapping server to fully represent the object in the sparse map.

Sparse map 800 may use a tag system to represent landmark types. In somecases, each traffic sign or directional sign may be associated with itsown tag, which may be stored in the database as part of the landmarkidentification. For example, the database may include on the order of1000 different tags to represent various traffic signs and on the orderof about 10000 different tags to represent directional signs. Of course,any suitable number of tags may be used, and additional tags may becreated as needed. General purpose signs may be represented in someembodiments using less than about 100 bytes (e.g., about 86 bytesincluding 8 bytes for size; 12 bytes for distance to previous landmark,lateral offset, and height; 50 bytes for an image signature; and 16bytes for GPS coordinates).

Thus, for semantic road signs not requiring an image signature, the datadensity impact to sparse map 800, even at relatively high landmarkdensities of about 1 per 50 m, may be on the order of about 760 bytesper kilometer (e.g., 20 landmarks per km×38 bytes per landmark=760bytes). Even for general purpose signs including an image signaturecomponent, the data density impact is about 1.72 kB per km (e.g., 20landmarks per km×86 bytes per landmark=1,720 bytes). For semantic roadsigns, this equates to about 76 kB per hour of data usage for a vehicletraveling 100 km/hr. For general purpose signs, this equates to about170 kB per hour for a vehicle traveling 100 km/hr. It should be notedthat in some environments (e.g., urban environments) there may be a muchhigher density of detected objects available for inclusion in the sparsemap (perhaps more than one per meter). In some embodiments, a generallyrectangular object, such as a rectangular sign, may be represented insparse map 800 by no more than 100 bytes of data. The representation ofthe generally rectangular object (e.g., general sign 1040) in sparse map800 may include a condensed image signature or image hash (e.g.,condensed image signature 1045) associated with the generallyrectangular object. This condensed image signature/image hash may bedetermined using any suitable image hashing algorithm and may be used,for example, to aid in identification of a general purpose sign, forexample, as a recognized landmark. Such a condensed image signature(e.g., image information derived from actual image data representing anobject) may avoid a need for storage of an actual image of an object ora need for comparative image analysis performed on actual images inorder to recognize landmarks.

Referring to FIG. 10 , sparse map 800 may include or store a condensedimage signature 1045 associated with a general sign 1040, rather than anactual image of general sign 1040. For example, after an image capturedevice (e.g., image capture device 122, 124, or 126) captures an imageof general sign 1040, a processor (e.g., image processor 190 or anyother processor that can process images either aboard or remotelylocated relative to a host vehicle) may perform an image analysis toextract/create condensed image signature 1045 that includes a uniquesignature or pattern associated with general sign 1040. In oneembodiment, condensed image signature 1045 may include a shape, colorpattern, a brightness pattern, or any other feature that may beextracted from the image of general sign 1040 for describing generalsign 1040.

For example, in FIG. 10 , the circles, triangles, and stars shown incondensed image signature 1045 may represent areas of different colors.The pattern represented by the circles, triangles, and stars may bestored in sparse map 800, e.g., within the 50 bytes designated toinclude an image signature. Notably, the circles, triangles, and starsare not necessarily meant to indicate that such shapes are stored aspart of the image signature. Rather, these shapes are meant toconceptually represent recognizable areas having discernible colordifferences, textual areas, graphical shapes, or other variations incharacteristics that may be associated with a general purpose sign. Suchcondensed image signatures can be used to identify a landmark in theform of a general sign. For example, the condensed image signature canbe used to perform a same-not-same analysis based on a comparison of astored condensed image signature with image data captured, for example,using a camera onboard an autonomous vehicle.

Accordingly, the plurality of landmarks may be identified through imageanalysis of the plurality of images acquired as one or more vehiclestraverse the road segment. As explained below with respect to“crowdsourcing,” in some embodiments, the image analysis to identify theplurality of landmarks may include accepting potential landmarks when aratio of images in which the landmark does appear to images in which thelandmark does not appear exceeds a threshold. Furthermore, in someembodiments, the image analysis to identify the plurality of landmarksmay include rejecting potential landmarks when a ratio of images inwhich the landmark does not appear to images in which the landmark doesappear exceeds a threshold.

Returning to the target trajectories a host vehicle may use to navigatea particular road segment, FIG. 11A shows polynomial representationstrajectories capturing during a process of building or maintainingsparse map 800. A polynomial representation of a target trajectoryincluded in sparse map 800 may be determined based on two or morereconstructed trajectories of prior traversals of vehicles along thesame road segment. In some embodiments, the polynomial representation ofthe target trajectory included in sparse map 800 may be an aggregationof two or more reconstructed trajectories of prior traversals ofvehicles along the same road segment. In some embodiments, thepolynomial representation of the target trajectory included in sparsemap 800 may be an average of the two or more reconstructed trajectoriesof prior traversals of vehicles along the same road segment. Othermathematical operations may also be used to construct a targettrajectory along a road path based on reconstructed trajectoriescollected from vehicles traversing along a road segment.

As shown in FIG. 11A, a road segment 1100 may be travelled by a numberof vehicles 200 at different times. Each vehicle 200 may collect datarelating to a path that the vehicle took along the road segment. Thepath traveled by a particular vehicle may be determined based on cameradata, accelerometer information, speed sensor information, and/or GPSinformation, among other potential sources. Such data may be used toreconstruct trajectories of vehicles traveling along the road segment,and based on these reconstructed trajectories, a target trajectory (ormultiple target trajectories) may be determined for the particular roadsegment. Such target trajectories may represent a preferred path of ahost vehicle (e.g., guided by an autonomous navigation system) as thevehicle travels along the road segment.

In the example shown in FIG. 11A, a first reconstructed trajectory 1101may be determined based on data received from a first vehicle traversingroad segment 1100 at a first time period (e.g., day 1), a secondreconstructed trajectory 1102 may be obtained from a second vehicletraversing road segment 1100 at a second time period (e.g., day 2), anda third reconstructed trajectory 1103 may be obtained from a thirdvehicle traversing road segment 1100 at a third time period (e.g., day3). Each trajectory 1101, 1102, and 1103 may be represented by apolynomial, such as a three-dimensional polynomial. It should be notedthat in some embodiments, any of the reconstructed trajectories may beassembled onboard the vehicles traversing road segment 1100.

Additionally, or alternatively, such reconstructed trajectories may bedetermined on a server side based on information received from vehiclestraversing road segment 1100. For example, in some embodiments, vehicles200 may transmit data to one or more servers relating to their motionalong road segment 1100 (e.g., steering angle, heading, time, position,speed, sensed road geometry, and/or sensed landmarks, among things). Theserver may reconstruct trajectories for vehicles 200 based on thereceived data. The server may also generate a target trajectory forguiding navigation of autonomous vehicle that will travel along the sameroad segment 1100 at a later time based on the first, second, and thirdtrajectories 1101, 1102, and 1103. While a target trajectory may beassociated with a single prior traversal of a road segment, in someembodiments, each target trajectory included in sparse map 800 may bedetermined based on two or more reconstructed trajectories of vehiclestraversing the same road segment. In FIG. 11A, the target trajectory isrepresented by 1110. In some embodiments, the target trajectory 1110 maybe generated based on an average of the first, second, and thirdtrajectories 1101, 1102, and 1103. In some embodiments, the targettrajectory 1110 included in sparse map 800 may be an aggregation (e.g.,a weighted combination) of two or more reconstructed trajectories.

At the mapping server, the server may receive actual trajectories for aparticular road segment from multiple harvesting vehicles traversing theroad segment. To generate a target trajectory for each valid path alongthe road segment (e.g., each lane, each drive direction, each paththrough a junction, etc.), the received actual trajectories may bealigned. The alignment process may include using detectedobjects/features identified along the road segment along with harvestedpositions of those detected objects/features to correlate the actual,harvested trajectories with one another. Once aligned, an average or“best fit” target trajectory for each available lane, etc. may bedetermined based on the aggregated, correlated/aligned actualtrajectories.

FIGS. 11B and 11C further illustrate the concept of target trajectoriesassociated with road segments present within a geographic region 1111.As shown in FIG. 11B, a first road segment 1120 within geographic region1111 may include a multilane road, which includes two lanes 1122designated for vehicle travel in a first direction and two additionallanes 1124 designated for vehicle travel in a second direction oppositeto the first direction. Lanes 1122 and lanes 1124 may be separated by adouble yellow line 1123. Geographic region 1111 may also include abranching road segment 1130 that intersects with road segment 1120. Roadsegment 1130 may include a two-lane road, each lane being designated fora different direction of travel. Geographic region 1111 may also includeother road features, such as a stop line 1132, a stop sign 1134, a speedlimit sign 1136, and a hazard sign 1138.

As shown in FIG. 11C, sparse map 800 may include a local map 1140including a road model for assisting with autonomous navigation ofvehicles within geographic region 1111. For example, local map 1140 mayinclude target trajectories for one or more lanes associated with roadsegments 1120 and/or 1130 within geographic region 1111. For example,local map 1140 may include target trajectories 1141 and/or 1142 that anautonomous vehicle may access or rely upon when traversing lanes 1122.Similarly, local map 1140 may include target trajectories 1143 and/or1144 that an autonomous vehicle may access or rely upon when traversinglanes 1124. Further, local map 1140 may include target trajectories 1145and/or 1146 that an autonomous vehicle may access or rely upon whentraversing road segment 1130. Target trajectory 1147 represents apreferred path an autonomous vehicle should follow when transitioningfrom lanes 1120 (and specifically, relative to target trajectory 1141associated with a right-most lane of lanes 1120) to road segment 1130(and specifically, relative to a target trajectory 1145 associated witha first side of road segment 1130. Similarly, target trajectory 1148represents a preferred path an autonomous vehicle should follow whentransitioning from road segment 1130 (and specifically, relative totarget trajectory 1146) to a portion of road segment 1124 (andspecifically, as shown, relative to a target trajectory 1143 associatedwith a left lane of lanes 1124.

Sparse map 800 may also include representations of other road-relatedfeatures associated with geographic region 1111. For example, sparse map800 may also include representations of one or more landmarks identifiedin geographic region 1111. Such landmarks may include a first landmark1150 associated with stop line 1132, a second landmark 1152 associatedwith stop sign 1134, a third landmark associated with speed limit sign1154, and a fourth landmark 1156 associated with hazard sign 1138. Suchlandmarks may be used, for example, to assist an autonomous vehicle indetermining its current location relative to any of the shown targettrajectories, such that the vehicle may adjust its heading to match adirection of the target trajectory at the determined location.

In some embodiments, sparse map 800 may also include road signatureprofiles. Such road signature profiles may be associated with anydiscernible/measurable variation in at least one parameter associatedwith a road. For example, in some cases, such profiles may be associatedwith variations in road surface information such as variations insurface roughness of a particular road segment, variations in road widthover a particular road segment, variations in distances between dashedlines painted along a particular road segment, variations in roadcurvature along a particular road segment, etc. FIG. 11D shows anexample of a road signature profile 1160. While profile 1160 mayrepresent any of the parameters mentioned above, or others, in oneexample, profile 1160 may represent a measure of road surface roughness,as obtained, for example, by monitoring one or more sensors providingoutputs indicative of an amount of suspension displacement as a vehicletravels a particular road segment.

Alternatively or concurrently, profile 1160 may represent variation inroad width, as determined based on image data obtained via a cameraonboard a vehicle traveling a particular road segment. Such profiles maybe useful, for example, in determining a particular location of anautonomous vehicle relative to a particular target trajectory. That is,as it traverses a road segment, an autonomous vehicle may measure aprofile associated with one or more parameters associated with the roadsegment. If the measured profile can be correlated/matched with apredetermined profile that plots the parameter variation with respect toposition along the road segment, then the measured and predeterminedprofiles may be used (e.g., by overlaying corresponding sections of themeasured and predetermined profiles) in order to determine a currentposition along the road segment and, therefore, a current positionrelative to a target trajectory for the road segment.

In some embodiments, sparse map 800 may include different trajectoriesbased on different characteristics associated with a user of autonomousvehicles, environmental conditions, and/or other parameters relating todriving. For example, in some embodiments, different trajectories may begenerated based on different user preferences and/or profiles. Sparsemap 800 including such different trajectories may be provided todifferent autonomous vehicles of different users. For example, someusers may prefer to avoid toll roads, while others may prefer to takethe shortest or fastest routes, regardless of whether there is a tollroad on the route. The disclosed systems may generate different sparsemaps with different trajectories based on such different userpreferences or profiles. As another example, some users may prefer totravel in a fast moving lane, while others may prefer to maintain aposition in the central lane at all times.

Different trajectories may be generated and included in sparse map 800based on different environmental conditions, such as day and night,snow, rain, fog, etc. Autonomous vehicles driving under differentenvironmental conditions may be provided with sparse map 800 generatedbased on such different environmental conditions. In some embodiments,cameras provided on autonomous vehicles may detect the environmentalconditions, and may provide such information back to a server thatgenerates and provides sparse maps. For example, the server may generateor update an already generated sparse map 800 to include trajectoriesthat may be more suitable or safer for autonomous driving under thedetected environmental conditions. The update of sparse map 800 based onenvironmental conditions may be performed dynamically as the autonomousvehicles are traveling along roads.

Other different parameters relating to driving may also be used as abasis for generating and providing different sparse maps to differentautonomous vehicles. For example, when an autonomous vehicle istraveling at a high speed, turns may be tighter. Trajectories associatedwith specific lanes, rather than roads, may be included in sparse map800 such that the autonomous vehicle may maintain within a specific laneas the vehicle follows a specific trajectory. When an image captured bya camera onboard the autonomous vehicle indicates that the vehicle hasdrifted outside of the lane (e.g., crossed the lane mark), an action maybe triggered within the vehicle to bring the vehicle back to thedesignated lane according to the specific trajectory.

Crowdsourcing a Sparse Map

The disclosed sparse maps may be efficiently (and passively) generatedthrough the power of crowdsourcing. For example, any private orcommercial vehicle equipped with a camera (e.g., a simple, lowresolution camera regularly included as OEM equipment on today'svehicles) and an appropriate image analysis processor can serve as aharvesting vehicle. No special equipment (e.g., high definition imagingand/or positioning systems) are required. As a result of the disclosedcrowdsourcing technique, the generated sparse maps may be extremelyaccurate and may include extremely refined position information(enabling navigation error limits of 10 cm or less) without requiringany specialized imaging or sensing equipment as input to the mapgeneration process. Crowdsourcing also enables much more rapid (andinexpensive) updates to the generated maps, as new drive information iscontinuously available to the mapping server system from any roadstraversed by private or commercial vehicles minimally equipped to alsoserve as harvesting vehicles. There is no need for designated vehiclesequipped with high-definition imaging and mapping sensors. Therefore,the expense associated with building such specialized vehicles can beavoided. Further, updates to the presently disclosed sparse maps may bemade much more rapidly than systems that rely upon dedicated,specialized mapping vehicles (which by virtue of their expense andspecial equipment are typically limited to a fleet of specializedvehicles of far lower numbers than the number of private or commercialvehicles already available for performing the disclosed harvestingtechniques).

The disclosed sparse maps generated through crowdsourcing may beextremely accurate because they may be generated based on many inputsfrom multiple (10 s, hundreds, millions, etc.) of harvesting vehiclesthat have collected drive information along a particular road segment.For example, every harvesting vehicle that drives along a particularroad segment may record its actual trajectory and may determine positioninformation relative to detected objects/features along the roadsegment. This information is passed along from multiple harvestingvehicles to a server. The actual trajectories are aggregated to generatea refined, target trajectory for each valid drive path along the roadsegment. Additionally, the position information collected from themultiple harvesting vehicles for each of the detected objects/featuresalong the road segment (semantic or non-semantic) can also beaggregated. As a result, the mapped position of each detectedobject/feature may constitute an average of hundreds, thousands, ormillions of individually determined positions for each detectedobject/feature. Such a technique may yield extremely accurate mappedpositions for the detected objects/features.

In some embodiments, the disclosed systems and methods may generate asparse map for autonomous vehicle navigation. For example, disclosedsystems and methods may use crowdsourced data for generation of a sparsemap that one or more autonomous vehicles may use to navigate along asystem of roads. As used herein, “crowdsourcing” means that data arereceived from various vehicles (e.g., autonomous vehicles) travelling ona road segment at different times, and such data are used to generateand/or update the road model, including sparse map tiles. The model orany of its sparse map tiles may, in turn, be transmitted to the vehiclesor other vehicles later travelling along the road segment for assistingautonomous vehicle navigation. The road model may include a plurality oftarget trajectories representing preferred trajectories that autonomousvehicles should follow as they traverse a road segment. The targettrajectories may be the same as a reconstructed actual trajectorycollected from a vehicle traversing a road segment, which may betransmitted from the vehicle to a server. In some embodiments, thetarget trajectories may be different from actual trajectories that oneor more vehicles previously took when traversing a road segment. Thetarget trajectories may be generated based on actual trajectories (e.g.,through averaging or any other suitable operation).

The vehicle trajectory data that a vehicle may upload to a server maycorrespond with the actual reconstructed trajectory for the vehicle ormay correspond to a recommended trajectory, which may be based on orrelated to the actual reconstructed trajectory of the vehicle, but maydiffer from the actual reconstructed trajectory. For example, vehiclesmay modify their actual, reconstructed trajectories and submit (e.g.,recommend) to the server the modified actual trajectories. The roadmodel may use the recommended, modified trajectories as targettrajectories for autonomous navigation of other vehicles.

In addition to trajectory information, other information for potentialuse in building a sparse data map 800 may include information relatingto potential landmark candidates. For example, through crowd sourcing ofinformation, the disclosed systems and methods may identify potentiallandmarks in an environment and refine landmark positions. The landmarksmay be used by a navigation system of autonomous vehicles to determineand/or adjust the position of the vehicle along the target trajectories.

The reconstructed trajectories that a vehicle may generate as thevehicle travels along a road may be obtained by any suitable method. Insome embodiments, the reconstructed trajectories may be developed bystitching together segments of motion for the vehicle, using, e.g., egomotion estimation (e.g., three dimensional translation and threedimensional rotation of the camera, and hence the body of the vehicle).The rotation and translation estimation may be determined based onanalysis of images captured by one or more image capture devices alongwith information from other sensors or devices, such as inertial sensorsand speed sensors. For example, the inertial sensors may include anaccelerometer or other suitable sensors configured to measure changes intranslation and/or rotation of the vehicle body. The vehicle may includea speed sensor that measures a speed of the vehicle.

In some embodiments, the ego motion of the camera (and hence the vehiclebody) may be estimated based on an optical flow analysis of the capturedimages. An optical flow analysis of a sequence of images identifiesmovement of pixels from the sequence of images, and based on theidentified movement, determines motions of the vehicle. The ego motionmay be integrated over time and along the road segment to reconstruct atrajectory associated with the road segment that the vehicle hasfollowed.

Data (e.g., reconstructed trajectories) collected by multiple vehiclesin multiple drives along a road segment at different times may be usedto construct the road model (e.g., including the target trajectories,etc.) included in sparse data map 800. Data collected by multiplevehicles in multiple drives along a road segment at different times mayalso be averaged to increase an accuracy of the model. In someembodiments, data regarding the road geometry and/or landmarks may bereceived from multiple vehicles that travel through the common roadsegment at different times. Such data received from different vehiclesmay be combined to generate the road model and/or to update the roadmodel.

The geometry of a reconstructed trajectory (and also a targettrajectory) along a road segment may be represented by a curve in threedimensional space, which may be a spline connecting three dimensionalpolynomials. The reconstructed trajectory curve may be determined fromanalysis of a video stream or a plurality of images captured by a camerainstalled on the vehicle. In some embodiments, a location is identifiedin each frame or image that is a few meters ahead of the currentposition of the vehicle. This location is where the vehicle is expectedto travel to in a predetermined time period. This operation may berepeated frame by frame, and at the same time, the vehicle may computethe camera's ego motion (rotation and translation). At each frame orimage, a short range model for the desired path is generated by thevehicle in a reference frame that is attached to the camera. The shortrange models may be stitched together to obtain a three dimensionalmodel of the road in some coordinate frame, which may be an arbitrary orpredetermined coordinate frame. The three dimensional model of the roadmay then be fitted by a spline, which may include or connect one or morepolynomials of suitable orders.

To conclude the short range road model at each frame, one or moredetection modules may be used. For example, a bottom-up lane detectionmodule may be used. The bottom-up lane detection module may be usefulwhen lane marks are drawn on the road. This module may look for edges inthe image and assembles them together to form the lane marks. A secondmodule may be used together with the bottom-up lane detection module.The second module is an end-to-end deep neural network, which may betrained to predict the correct short range path from an input image. Inboth modules, the road model may be detected in the image coordinateframe and transformed to a three dimensional space that may be virtuallyattached to the camera.

Although the reconstructed trajectory modeling method may introduce anaccumulation of errors due to the integration of ego motion over a longperiod of time, which may include a noise component, such errors may beinconsequential as the generated model may provide sufficient accuracyfor navigation over a local scale. In addition, it is possible to cancelthe integrated error by using external sources of information, such assatellite images or geodetic measurements. For example, the disclosedsystems and methods may use a GNSS receiver to cancel accumulatederrors. However, the GNSS positioning signals may not be alwaysavailable and accurate. The disclosed systems and methods may enable asteering application that depends weakly on the availability andaccuracy of GNSS positioning. In such systems, the usage of the GNSSsignals may be limited. For example, in some embodiments, the disclosedsystems may use the GNSS signals for database indexing purposes only.

In some embodiments, the range scale (e.g., local scale) that may berelevant for an autonomous vehicle navigation steering application maybe on the order of 50 meters, 100 meters, 200 meters, 300 meters, etc.Such distances may be used, as the geometrical road model is mainly usedfor two purposes: planning the trajectory ahead and localizing thevehicle on the road model. In some embodiments, the planning task mayuse the model over a typical range of 40 meters ahead (or any othersuitable distance ahead, such as 20 meters, 30 meters, 50 meters), whenthe control algorithm steers the vehicle according to a target pointlocated 1.3 seconds ahead (or any other time such as 1.5 seconds, 1.7seconds, 2 seconds, etc.). The localization task uses the road modelover a typical range of 60 meters behind the car (or any other suitabledistances, such as 50 meters, 100 meters, 150 meters, etc.), accordingto a method called “tail alignment” described in more detail in anothersection. The disclosed systems and methods may generate a geometricalmodel that has sufficient accuracy over particular range, such as 100meters, such that a planned trajectory will not deviate by more than,for example, 30 cm from the lane center.

As explained above, a three dimensional road model may be constructedfrom detecting short range sections and stitching them together. Thestitching may be enabled by computing a six degree ego motion model,using the videos and/or images captured by the camera, data from theinertial sensors that reflect the motions of the vehicle, and the hostvehicle velocity signal. The accumulated error may be small enough oversome local range scale, such as of the order of 100 meters. All this maybe completed in a single drive over a particular road segment.

In some embodiments, multiple drives may be used to average the resultedmodel, and to increase its accuracy further. The same car may travel thesame route multiple times, or multiple cars may send their collectedmodel data to a central server. In any case, a matching procedure may beperformed to identify overlapping models and to enable averaging inorder to generate target trajectories. The constructed model (e.g.,including the target trajectories) may be used for steering once aconvergence criterion is met. Subsequent drives may be used for furthermodel improvements and in order to accommodate infrastructure changes.

Sharing of driving experience (such as sensed data) between multiplecars becomes feasible if they are connected to a central server. Eachvehicle client may store a partial copy of a universal road model, whichmay be relevant for its current position. A bidirectional updateprocedure between the vehicles and the server may be performed by thevehicles and the server. The small footprint concept discussed aboveenables the disclosed systems and methods to perform the bidirectionalupdates using a very small bandwidth.

Information relating to potential landmarks may also be determined andforwarded to a central server. For example, the disclosed systems andmethods may determine one or more physical properties of a potentiallandmark based on one or more images that include the landmark. Thephysical properties may include a physical size (e.g., height, width) ofthe landmark, a distance from a vehicle to a landmark, a distancebetween the landmark to a previous landmark, the lateral position of thelandmark (e.g., the position of the landmark relative to the lane oftravel), the GPS coordinates of the landmark, a type of landmark,identification of text on the landmark, etc. For example, a vehicle mayanalyze one or more images captured by a camera to detect a potentiallandmark, such as a speed limit sign.

The vehicle may determine a distance from the vehicle to the landmark ora position associated with the landmark (e.g., any semantic ornon-semantic object or feature along a road segment) based on theanalysis of the one or more images. In some embodiments, the distancemay be determined based on analysis of images of the landmark using asuitable image analysis method, such as a scaling method and/or anoptical flow method. As previously noted, a position of theobject/feature may include a 2D image position (e.g., an X-Y pixelposition in one or more captured images) of one or more pointsassociated with the object/feature or may include a 3D real-worldposition of one or more points (e.g., determined through structure inmotion/optical flow techniques, LIDAR or RADAR information, etc.). Insome embodiments, the disclosed systems and methods may be configured todetermine a type or classification of a potential landmark. In case thevehicle determines that a certain potential landmark corresponds to apredetermined type or classification stored in a sparse map, it may besufficient for the vehicle to communicate to the server an indication ofthe type or classification of the landmark, along with its location. Theserver may store such indications. At a later time, during navigation, anavigating vehicle may capture an image that includes a representationof the landmark, process the image (e.g., using a classifier), andcompare the result landmark in order to confirm detection of the mappedlandmark and to use the mapped landmark in localizing the navigatingvehicle relative to the sparse map.

In some embodiments, multiple autonomous vehicles travelling on a roadsegment may communicate with a server. The vehicles (or clients) maygenerate a curve describing its drive (e.g., through ego motionintegration) in an arbitrary coordinate frame. The vehicles may detectlandmarks and locate them in the same frame. The vehicles may upload thecurve and the landmarks to the server. The server may collect data fromvehicles over multiple drives, and generate a unified road model. Forexample, as discussed below with respect to FIG. 19 , the server maygenerate a sparse map having the unified road model using the uploadedcurves and landmarks.

The server may also distribute the model to clients (e.g., vehicles).For example, the server may distribute the sparse map to one or morevehicles. The server may continuously or periodically update the modelwhen receiving new data from the vehicles. For example, the server mayprocess the new data to evaluate whether the data includes informationthat should trigger an updated, or creation of new data on the server.The server may distribute the updated model or the updates to thevehicles for providing autonomous vehicle navigation.

The server may use one or more criteria for determining whether new datareceived from the vehicles should trigger an update to the model ortrigger creation of new data. For example, when the new data indicatesthat a previously recognized landmark at a specific location no longerexists, or is replaced by another landmark, the server may determinethat the new data should trigger an update to the model. As anotherexample, when the new data indicates that a road segment has beenclosed, and when this has been corroborated by data received from othervehicles, the server may determine that the new data should trigger anupdate to the model.

The server may distribute the updated model (or the updated portion ofthe model) to one or more vehicles that are traveling on the roadsegment, with which the updates to the model are associated. The servermay also distribute the updated model to vehicles that are about totravel on the road segment, or vehicles whose planned trip includes theroad segment, with which the updates to the model are associated. Forexample, while an autonomous vehicle is traveling along another roadsegment before reaching the road segment with which an update isassociated, the server may distribute the updates or updated model tothe autonomous vehicle before the vehicle reaches the road segment.

In some embodiments, the remote server may collect trajectories andlandmarks from multiple clients (e.g., vehicles that travel along acommon road segment). The server may match curves using landmarks andcreate an average road model based on the trajectories collected fromthe multiple vehicles. The server may also compute a graph of roads andthe most probable path at each node or conjunction of the road segment.For example, the remote server may align the trajectories to generate acrowdsourced sparse map from the collected trajectories.

The server may average landmark properties received from multiplevehicles that travelled along the common road segment, such as thedistances between one landmark to another (e.g., a previous one alongthe road segment) as measured by multiple vehicles, to determine anarc-length parameter and support localization along the path and speedcalibration for each client vehicle. The server may average the physicaldimensions of a landmark measured by multiple vehicles travelled alongthe common road segment and recognized the same landmark. The averagedphysical dimensions may be used to support distance estimation, such asthe distance from the vehicle to the landmark. The server may averagelateral positions of a landmark (e.g., position from the lane in whichvehicles are travelling in to the landmark) measured by multiplevehicles travelled along the common road segment and recognized the samelandmark. The averaged lateral potion may be used to support laneassignment. The server may average the GPS coordinates of the landmarkmeasured by multiple vehicles travelled along the same road segment andrecognized the same landmark. The averaged GPS coordinates of thelandmark may be used to support global localization or positioning ofthe landmark in the road model.

In some embodiments, the server may identify model changes, such asconstructions, detours, new signs, removal of signs, etc., based on datareceived from the vehicles. The server may continuously or periodicallyor instantaneously update the model upon receiving new data from thevehicles. The server may distribute updates to the model or the updatedmodel to vehicles for providing autonomous navigation. For example, asdiscussed further below, the server may use crowdsourced data to filterout “ghost” landmarks detected by vehicles.

In some embodiments, the server may analyze driver interventions duringthe autonomous driving. The server may analyze data received from thevehicle at the time and location where intervention occurs, and/or datareceived prior to the time the intervention occurred. The server mayidentify certain portions of the data that caused or are closely relatedto the intervention, for example, data indicating a temporary laneclosure setup, data indicating a pedestrian in the road. The server mayupdate the model based on the identified data. For example, the servermay modify one or more trajectories stored in the model.

FIG. 12 is a schematic illustration of a system that uses crowdsourcingto generate a sparse map (as well as distribute and navigate using acrowdsourced sparse map). FIG. 12 shows a road segment 1200 thatincludes one or more lanes. A plurality of vehicles 1205, 1210, 1215,1220, and 1225 may travel on road segment 1200 at the same time or atdifferent times (although shown as appearing on road segment 1200 at thesame time in FIG. 12 ). At least one of vehicles 1205, 1210, 1215, 1220,and 1225 may be an autonomous vehicle. For simplicity of the presentexample, all of the vehicles 1205, 1210, 1215, 1220, and 1225 arepresumed to be autonomous vehicles.

Each vehicle may be similar to vehicles disclosed in other embodiments(e.g., vehicle 200), and may include components or devices included inor associated with vehicles disclosed in other embodiments. Each vehiclemay be equipped with an image capture device or camera (e.g., imagecapture device 122 or camera 122). Each vehicle may communicate with aremote server 1230 via one or more networks (e.g., over a cellularnetwork and/or the Internet, etc.) through wireless communication paths1235, as indicated by the dashed lines. Each vehicle may transmit datato server 1230 and receive data from server 1230. For example, server1230 may collect data from multiple vehicles travelling on the roadsegment 1200 at different times, and may process the collected data togenerate an autonomous vehicle road navigation model, or an update tothe model. Server 1230 may transmit the autonomous vehicle roadnavigation model or the update to the model to the vehicles thattransmitted data to server 1230. Server 1230 may transmit the autonomousvehicle road navigation model or the update to the model to othervehicles that travel on road segment 1200 at later times.

As vehicles 1205, 1210, 1215, 1220, and 1225 travel on road segment1200, navigation information collected (e.g., detected, sensed, ormeasured) by vehicles 1205, 1210, 1215, 1220, and 1225 may betransmitted to server 1230. In some embodiments, the navigationinformation may be associated with the common road segment 1200. Thenavigation information may include a trajectory associated with each ofthe vehicles 1205, 1210, 1215, 1220, and 1225 as each vehicle travelsover road segment 1200. In some embodiments, the trajectory may bereconstructed based on data sensed by various sensors and devicesprovided on vehicle 1205. For example, the trajectory may bereconstructed based on at least one of accelerometer data, speed data,landmarks data, road geometry or profile data, vehicle positioning data,and ego motion data. In some embodiments, the trajectory may bereconstructed based on data from inertial sensors, such asaccelerometer, and the velocity of vehicle 1205 sensed by a speedsensor. In addition, in some embodiments, the trajectory may bedetermined (e.g., by a processor onboard each of vehicles 1205, 1210,1215, 1220, and 1225) based on sensed ego motion of the camera, whichmay indicate three dimensional translation and/or three dimensionalrotations (or rotational motions). The ego motion of the camera (andhence the vehicle body) may be determined from analysis of one or moreimages captured by the camera.

In some embodiments, the trajectory of vehicle 1205 may be determined bya processor provided aboard vehicle 1205 and transmitted to server 1230.In other embodiments, server 1230 may receive data sensed by the varioussensors and devices provided in vehicle 1205, and determine thetrajectory based on the data received from vehicle 1205.

In some embodiments, the navigation information transmitted fromvehicles 1205, 1210, 1215, 1220, and 1225 to server 1230 may includedata regarding the road surface, the road geometry, or the road profile.The geometry of road segment 1200 may include lane structure and/orlandmarks. The lane structure may include the total number of lanes ofroad segment 1200, the type of lanes (e.g., one-way lane, two-way lane,driving lane, passing lane, etc.), markings on lanes, width of lanes,etc. In some embodiments, the navigation information may include a laneassignment, e.g., which lane of a plurality of lanes a vehicle istraveling in. For example, the lane assignment may be associated with anumerical value “3” indicating that the vehicle is traveling on thethird lane from the left or right. As another example, the laneassignment may be associated with a text value “center lane” indicatingthe vehicle is traveling on the center lane.

Server 1230 may store the navigation information on a non-transitorycomputer-readable medium, such as a hard drive, a compact disc, a tape,a memory, etc. Server 1230 may generate (e.g., through a processorincluded in server 1230) at least a portion of an autonomous vehicleroad navigation model for the common road segment 1200 based on thenavigation information received from the plurality of vehicles 1205,1210, 1215, 1220, and 1225 and may store the model as a portion of asparse map. Server 1230 may determine a trajectory associated with eachlane based on crowdsourced data (e.g., navigation information) receivedfrom multiple vehicles (e.g., 1205, 1210, 1215, 1220, and 1225) thattravel on a lane of road segment at different times. Server 1230 maygenerate the autonomous vehicle road navigation model or a portion ofthe model (e.g., an updated portion) based on a plurality oftrajectories determined based on the crowd sourced navigation data.Server 1230 may transmit the model or the updated portion of the modelto one or more of autonomous vehicles 1205, 1210, 1215, 1220, and 1225traveling on road segment 1200 or any other autonomous vehicles thattravel on road segment at a later time for updating an existingautonomous vehicle road navigation model provided in a navigation systemof the vehicles. The autonomous vehicle road navigation model may beused by the autonomous vehicles in autonomously navigating along thecommon road segment 1200.

As explained above, the autonomous vehicle road navigation model may beincluded in a sparse map (e.g., sparse map 800 depicted in FIG. 8 ).Sparse map 800 may include sparse recording of data related to roadgeometry and/or landmarks along a road, which may provide sufficientinformation for guiding autonomous navigation of an autonomous vehicle,yet does not require excessive data storage. In some embodiments, theautonomous vehicle road navigation model may be stored separately fromsparse map 800, and may use map data from sparse map 800 when the modelis executed for navigation. In some embodiments, the autonomous vehicleroad navigation model may use map data included in sparse map 800 fordetermining target trajectories along road segment 1200 for guidingautonomous navigation of autonomous vehicles 1205, 1210, 1215, 1220, and1225 or other vehicles that later travel along road segment 1200. Forexample, when the autonomous vehicle road navigation model is executedby a processor included in a navigation system of vehicle 1205, themodel may cause the processor to compare the trajectories determinedbased on the navigation information received from vehicle 1205 withpredetermined trajectories included in sparse map 800 to validate and/orcorrect the current traveling course of vehicle 1205.

In the autonomous vehicle road navigation model, the geometry of a roadfeature or target trajectory may be encoded by a curve in athree-dimensional space. In one embodiment, the curve may be a threedimensional spline including one or more connecting three dimensionalpolynomials. As one of skill in the art would understand, a spline maybe a numerical function that is piece-wise defined by a series ofpolynomials for fitting data. A spline for fitting the three dimensionalgeometry data of the road may include a linear spline (first order), aquadratic spline (second order), a cubic spline (third order), or anyother splines (other orders), or a combination thereof. The spline mayinclude one or more three dimensional polynomials of different ordersconnecting (e.g., fitting) data points of the three dimensional geometrydata of the road. In some embodiments, the autonomous vehicle roadnavigation model may include a three dimensional spline corresponding toa target trajectory along a common road segment (e.g., road segment1200) or a lane of the road segment 1200.

As explained above, the autonomous vehicle road navigation modelincluded in the sparse map may include other information, such asidentification of at least one landmark along road segment 1200. Thelandmark may be visible within a field of view of a camera (e.g., camera122) installed on each of vehicles 1205, 1210, 1215, 1220, and 1225. Insome embodiments, camera 122 may capture an image of a landmark. Aprocessor (e.g., processor 180, 190, or processing unit 110) provided onvehicle 1205 may process the image of the landmark to extractidentification information for the landmark. The landmark identificationinformation, rather than an actual image of the landmark, may be storedin sparse map 800. The landmark identification information may requiremuch less storage space than an actual image. Other sensors or systems(e.g., GPS system) may also provide certain identification informationof the landmark (e.g., position of landmark). The landmark may includeat least one of a traffic sign, an arrow marking, a lane marking, adashed lane marking, a traffic light, a stop line, a directional sign(e.g., a highway exit sign with an arrow indicating a direction, ahighway sign with arrows pointing to different directions or places), alandmark beacon, or a lamppost. A landmark beacon refers to a device(e.g., an RFID device) installed along a road segment that transmits orreflects a signal to a receiver installed on a vehicle, such that whenthe vehicle passes by the device, the beacon received by the vehicle andthe location of the device (e.g., determined from GPS location of thedevice) may be used as a landmark to be included in the autonomousvehicle road navigation model and/or the sparse map 800.

The identification of at least one landmark may include a position ofthe at least one landmark. The position of the landmark may bedetermined based on position measurements performed using sensor systems(e.g., Global Positioning Systems, inertial based positioning systems,landmark beacon, etc.) associated with the plurality of vehicles 1205,1210, 1215, 1220, and 1225. In some embodiments, the position of thelandmark may be determined by averaging the position measurementsdetected, collected, or received by sensor systems on different vehicles1205, 1210, 1215, 1220, and 1225 through multiple drives. For example,vehicles 1205, 1210, 1215, 1220, and 1225 may transmit positionmeasurements data to server 1230, which may average the positionmeasurements and use the averaged position measurement as the positionof the landmark. The position of the landmark may be continuouslyrefined by measurements received from vehicles in subsequent drives.

The identification of the landmark may include a size of the landmark.The processor provided on a vehicle (e.g., 1205) may estimate thephysical size of the landmark based on the analysis of the images.Server 1230 may receive multiple estimates of the physical size of thesame landmark from different vehicles over different drives. Server 1230may average the different estimates to arrive at a physical size for thelandmark, and store that landmark size in the road model. The physicalsize estimate may be used to further determine or estimate a distancefrom the vehicle to the landmark. The distance to the landmark may beestimated based on the current speed of the vehicle and a scale ofexpansion based on the position of the landmark appearing in the imagesrelative to the focus of expansion of the camera. For example, thedistance to landmark may be estimated by Z=V*dt*R/D, where V is thespeed of vehicle, R is the distance in the image from the landmark attime t1 to the focus of expansion, and D is the change in distance forthe landmark in the image from t1 to t2. dt represents the (t2−t1). Forexample, the distance to landmark may be estimated by Z=V*dt*R/D, whereV is the speed of vehicle, R is the distance in the image between thelandmark and the focus of expansion, dt is a time interval, and D is theimage displacement of the landmark along the epipolar line. Otherequations equivalent to the above equation, such as Z=V*ω/Δω, may beused for estimating the distance to the landmark. Here, V is the vehiclespeed, w is an image length (like the object width), and Aw is thechange of that image length in a unit of time.

When the physical size of the landmark is known, the distance to thelandmark may also be determined based on the following equation:Z=f*W/ω, where f is the focal length, W is the size of the landmark(e.g., height or width), ω is the number of pixels when the landmarkleaves the image. From the above equation, a change in distance Z may becalculated using ΔZ=f*W*Δω/ω²+f*ΔW/ω), where ΔW decays to zero byaveraging, and where Δω is the number of pixels representing a boundingbox accuracy in the image. A value estimating the physical size of thelandmark may be calculated by averaging multiple observations at theserver side. The resulting error in distance estimation may be verysmall. There are two sources of error that may occur when using theformula above, namely ΔW and Δω. Their contribution to the distanceerror is given by ΔZ=f*W*Δω/ω²+f*ΔW/ω. However, ΔW decays to zero byaveraging; hence ΔZ is determined by Δω (e.g., the inaccuracy of thebounding box in the image).

For landmarks of unknown dimensions, the distance to the landmark may beestimated by tracking feature points on the landmark between successiveframes. For example, certain features appearing on a speed limit signmay be tracked between two or more image frames. Based on these trackedfeatures, a distance distribution per feature point may be generated.The distance estimate may be extracted from the distance distribution.For example, the most frequent distance appearing in the distancedistribution may be used as the distance estimate. As another example,the average of the distance distribution may be used as the distanceestimate.

FIG. 13 illustrates an example autonomous vehicle road navigation modelrepresented by a plurality of three dimensional splines 1301, 1302, and1303. The curves 1301, 1302, and 1303 shown in FIG. 13 are forillustration purpose only. Each spline may include one or more threedimensional polynomials connecting a plurality of data points 1310. Eachpolynomial may be a first order polynomial, a second order polynomial, athird order polynomial, or a combination of any suitable polynomialshaving different orders. Each data point 1310 may be associated with thenavigation information received from vehicles 1205, 1210, 1215, 1220,and 1225. In some embodiments, each data point 1310 may be associatedwith data related to landmarks (e.g., size, location, and identificationinformation of landmarks) and/or road signature profiles (e.g., roadgeometry, road roughness profile, road curvature profile, road widthprofile). In some embodiments, some data points 1310 may be associatedwith data related to landmarks, and others may be associated with datarelated to road signature profiles.

FIG. 14 illustrates raw location data 1410 (e.g., GPS data) receivedfrom five separate drives. One drive may be separate from another driveif it was traversed by separate vehicles at the same time, by the samevehicle at separate times, or by separate vehicles at separate times. Toaccount for errors in the location data 1410 and for differing locationsof vehicles within the same lane (e.g., one vehicle may drive closer tothe left of a lane than another), server 1230 may generate a mapskeleton 1420 using one or more statistical techniques to determinewhether variations in the raw location data 1410 represent actualdivergences or statistical errors. Each path within skeleton 1420 may belinked back to the raw data 1410 that formed the path. For example, thepath between A and B within skeleton 1420 is linked to raw data 1410from drives 2, 3, 4, and 5 but not from drive 1. Skeleton 1420 may notbe detailed enough to be used to navigate a vehicle (e.g., because itcombines drives from multiple lanes on the same road unlike the splinesdescribed above) but may provide useful topological information and maybe used to define intersections.

FIG. 15 illustrates an example by which additional detail may begenerated for a sparse map within a segment of a map skeleton (e.g.,segment A to B within skeleton 1420). As depicted in FIG. 15 , the data(e.g. ego-motion data, road markings data, and the like) may be shown asa function of position S (or S₁ or S₂) along the drive. Server 1230 mayidentify landmarks for the sparse map by identifying unique matchesbetween landmarks 1501, 1503, and 1505 of drive 1510 and landmarks 1507and 1509 of drive 1520. Such a matching algorithm may result inidentification of landmarks 1511, 1513, and 1515. One skilled in the artwould recognize, however, that other matching algorithms may be used.For example, probability optimization may be used in lieu of or incombination with unique matching. Server 1230 may longitudinally alignthe drives to align the matched landmarks. For example, server 1230 mayselect one drive (e.g., drive 1520) as a reference drive and then shiftand/or elastically stretch the other drive(s) (e.g., drive 1510) foralignment.

FIG. 16 shows an example of aligned landmark data for use in a sparsemap. In the example of FIG. 16 , landmark 1610 comprises a road sign.The example of FIG. 16 further depicts data from a plurality of drives1601, 1603, 1605, 1607, 1609, 1611, and 1613. In the example of FIG. 16, the data from drive 1613 consists of a “ghost” landmark, and theserver 1230 may identify it as such because none of drives 1601, 1603,1605, 1607, 1609, and 1611 include an identification of a landmark inthe vicinity of the identified landmark in drive 1613. Accordingly,server 1230 may accept potential landmarks when a ratio of images inwhich the landmark does appear to images in which the landmark does notappear exceeds a threshold and/or may reject potential landmarks when aratio of images in which the landmark does not appear to images in whichthe landmark does appear exceeds a threshold.

FIG. 17 depicts a system 1700 for generating drive data, which may beused to crowdsource a sparse map. As depicted in FIG. 17 , system 1700may include a camera 1701 and a locating device 1703 (e.g., a GPSlocator). Camera 1701 and locating device 1703 may be mounted on avehicle (e.g., one of vehicles 1205, 1210, 1215, 1220, and 1225). Camera1701 may produce a plurality of data of multiple types, e.g., ego motiondata, traffic sign data, road data, or the like. The camera data andlocation data may be segmented into drive segments 1705. For example,drive segments 1705 may each have camera data and location data fromless than 1 km of driving.

In some embodiments, system 1700 may remove redundancies in drivesegments 1705. For example, if a landmark appears in multiple imagesfrom camera 1701, system 1700 may strip the redundant data such that thedrive segments 1705 only contain one copy of the location of and anymetadata relating to the landmark. By way of further example, if a lanemarking appears in multiple images from camera 1701, system 1700 maystrip the redundant data such that the drive segments 1705 only containone copy of the location of and any metadata relating to the lanemarking.

System 1700 also includes a server (e.g., server 1230). Server 1230 mayreceive drive segments 1705 from the vehicle and recombine the drivesegments 1705 into a single drive 1707. Such an arrangement may allowfor reduce bandwidth requirements when transferring data between thevehicle and the server while also allowing for the server to store datarelating to an entire drive.

FIG. 18 depicts system 1700 of FIG. 17 further configured forcrowdsourcing a sparse map. As in FIG. 17 , system 1700 includes vehicle1810, which captures drive data using, for example, a camera (whichproduces, e.g., ego motion data, traffic sign data, road data, or thelike) and a locating device (e.g., a GPS locator). As in FIG. 17 ,vehicle 1810 segments the collected data into drive segments (depictedas “DS1 1,” “DS2 1,” “DSN 1” in FIG. 18 ). Server 1230 then receives thedrive segments and reconstructs a drive (depicted as “Drive 1” in FIG.18 ) from the received segments.

As further depicted in FIG. 18 , system 1700 also receives data fromadditional vehicles. For example, vehicle 1820 also captures drive datausing, for example, a camera (which produces, e.g., ego motion data,traffic sign data, road data, or the like) and a locating device (e.g.,a GPS locator). Similar to vehicle 1810, vehicle 1820 segments thecollected data into drive segments (depicted as “DS1 2,” “DS2 2,” “DSN2” in FIG. 18 ). Server 1230 then receives the drive segments andreconstructs a drive (depicted as “Drive 2” in FIG. 18 ) from thereceived segments. Any number of additional vehicles may be used. Forexample, FIG. 18 also includes “CAR N” that captures drive data,segments it into drive segments (depicted as “DS1 N,” “DS2 N,” “DSN N”in FIG. 18 ), and sends it to server 1230 for reconstruction into adrive (depicted as “Drive N” in FIG. 18 ).

As depicted in FIG. 18 , server 1230 may construct a sparse map(depicted as “MAP”) using the reconstructed drives (e.g., “Drive 1,”“Drive 2,” and “Drive N”) collected from a plurality of vehicles (e.g.,“CAR 1” (also labeled vehicle 1810), “CAR 2” (also labeled vehicle1820), and “CAR N”).

FIG. 19 is a flowchart showing an example process 1900 for generating asparse map for autonomous vehicle navigation along a road segment.Process 1900 may be performed by one or more processing devices includedin server 1230.

Process 1900 may include receiving a plurality of images acquired as oneor more vehicles traverse the road segment (step 1905). Server 1230 mayreceive images from cameras included within one or more of vehicles1205, 1210, 1215, 1220, and 1225. For example, camera 122 may captureone or more images of the environment surrounding vehicle 1205 asvehicle 1205 travels along road segment 1200. In some embodiments,server 1230 may also receive stripped down image data that has hadredundancies removed by a processor on vehicle 1205, as discussed abovewith respect to FIG. 17 .

Process 1900 may further include identifying, based on the plurality ofimages, at least one line representation of a road surface featureextending along the road segment (step 1910). Each line representationmay represent a path along the road segment substantially correspondingwith the road surface feature. For example, server 1230 may analyze theenvironmental images received from camera 122 to identify a road edge ora lane marking and determine a trajectory of travel along road segment1200 associated with the road edge or lane marking. In some embodiments,the trajectory (or line representation) may include a spline, apolynomial representation, or a curve. Server 1230 may determine thetrajectory of travel of vehicle 1205 based on camera ego motions (e.g.,three dimensional translation and/or three dimensional rotationalmotions) received at step 1905.

Process 1900 may also include identifying, based on the plurality ofimages, a plurality of landmarks associated with the road segment (step1910). For example, server 1230 may analyze the environmental imagesreceived from camera 122 to identify one or more landmarks, such as roadsign along road segment 1200. Server 1230 may identify the landmarksusing analysis of the plurality of images acquired as one or morevehicles traverse the road segment. To enable crowdsourcing, theanalysis may include rules regarding accepting and rejecting possiblelandmarks associated with the road segment. For example, the analysismay include accepting potential landmarks when a ratio of images inwhich the landmark does appear to images in which the landmark does notappear exceeds a threshold and/or rejecting potential landmarks when aratio of images in which the landmark does not appear to images in whichthe landmark does appear exceeds a threshold.

Process 1900 may include other operations or steps performed by server1230. For example, the navigation information may include a targettrajectory for vehicles to travel along a road segment, and process 1900may include clustering, by server 1230, vehicle trajectories related tomultiple vehicles travelling on the road segment and determining thetarget trajectory based on the clustered vehicle trajectories, asdiscussed in further detail below. Clustering vehicle trajectories mayinclude clustering, by server 1230, the multiple trajectories related tothe vehicles travelling on the road segment into a plurality of clustersbased on at least one of the absolute heading of vehicles or laneassignment of the vehicles. Generating the target trajectory may includeaveraging, by server 1230, the clustered trajectories. By way of furtherexample, process 1900 may include aligning data received in step 1905.Other processes or steps performed by server 1230, as described above,may also be included in process 1900.

The disclosed systems and methods may include other features. Forexample, the disclosed systems may use local coordinates, rather thanglobal coordinates. For autonomous driving, some systems may presentdata in world coordinates. For example, longitude and latitudecoordinates on the earth surface may be used. In order to use the mapfor steering, the host vehicle may determine its position andorientation relative to the map. It seems natural to use a GPS device onboard, in order to position the vehicle on the map and in order to findthe rotation transformation between the body reference frame and theworld reference frame (e.g., North, East and Down). Once the bodyreference frame is aligned with the map reference frame, then thedesired route may be expressed in the body reference frame and thesteering commands may be computed or generated.

The disclosed systems and methods may enable autonomous vehiclenavigation (e.g., steering control) with low footprint models, which maybe collected by the autonomous vehicles themselves without the aid ofexpensive surveying equipment. To support the autonomous navigation(e.g., steering applications), the road model may include a sparse maphaving the geometry of the road, its lane structure, and landmarks thatmay be used to determine the location or position of vehicles along atrajectory included in the model. As discussed above, generation of thesparse map may be performed by a remote server that communicates withvehicles travelling on the road and that receives data from thevehicles. The data may include sensed data, trajectories reconstructedbased on the sensed data, and/or recommended trajectories that mayrepresent modified reconstructed trajectories. As discussed below, theserver may transmit the model back to the vehicles or other vehiclesthat later travel on the road to aid in autonomous navigation.

FIG. 20 illustrates a block diagram of server 1230. Server 1230 mayinclude a communication unit 2005, which may include both hardwarecomponents (e.g., communication control circuits, switches, andantenna), and software components (e.g., communication protocols,computer codes). For example, communication unit 2005 may include atleast one network interface. Server 1230 may communicate with vehicles1205, 1210, 1215, 1220, and 1225 through communication unit 2005. Forexample, server 1230 may receive, through communication unit 2005,navigation information transmitted from vehicles 1205, 1210, 1215, 1220,and 1225. Server 1230 may distribute, through communication unit 2005,the autonomous vehicle road navigation model to one or more autonomousvehicles.

Server 1230 may include at least one non-transitory storage medium 2010,such as a hard drive, a compact disc, a tape, etc. Storage device 1410may be configured to store data, such as navigation information receivedfrom vehicles 1205, 1210, 1215, 1220, and 1225 and/or the autonomousvehicle road navigation model that server 1230 generates based on thenavigation information. Storage device 2010 may be configured to storeany other information, such as a sparse map (e.g., sparse map 800discussed above with respect to FIG. 8 ).

In addition to or in place of storage device 2010, server 1230 mayinclude a memory 2015. Memory 2015 may be similar to or different frommemory 140 or 150. Memory 2015 may be a non-transitory memory, such as aflash memory, a random access memory, etc. Memory 2015 may be configuredto store data, such as computer codes or instructions executable by aprocessor (e.g., processor 2020), map data (e.g., data of sparse map800), the autonomous vehicle road navigation model, and/or navigationinformation received from vehicles 1205, 1210, 1215, 1220, and 1225.

Server 1230 may include at least one processing device 2020 configuredto execute computer codes or instructions stored in memory 2015 toperform various functions. For example, processing device 2020 mayanalyze the navigation information received from vehicles 1205, 1210,1215, 1220, and 1225, and generate the autonomous vehicle roadnavigation model based on the analysis. Processing device 2020 maycontrol communication unit 1405 to distribute the autonomous vehicleroad navigation model to one or more autonomous vehicles (e.g., one ormore of vehicles 1205, 1210, 1215, 1220, and 1225 or any vehicle thattravels on road segment 1200 at a later time). Processing device 2020may be similar to or different from processor 180, 190, or processingunit 110.

FIG. 21 illustrates a block diagram of memory 2015, which may storecomputer code or instructions for performing one or more operations forgenerating a road navigation model for use in autonomous vehiclenavigation. As shown in FIG. 21 , memory 2015 may store one or moremodules for performing the operations for processing vehicle navigationinformation. For example, memory 2015 may include a model generatingmodule 2105 and a model distributing module 2110. Processor 2020 mayexecute the instructions stored in any of modules 2105 and 2110 includedin memory 2015.

Model generating module 2105 may store instructions which, when executedby processor 2020, may generate at least a portion of an autonomousvehicle road navigation model for a common road segment (e.g., roadsegment 1200) based on navigation information received from vehicles1205, 1210, 1215, 1220, and 1225. For example, in generating theautonomous vehicle road navigation model, processor 2020 may clustervehicle trajectories along the common road segment 1200 into differentclusters. Processor 2020 may determine a target trajectory along thecommon road segment 1200 based on the clustered vehicle trajectories foreach of the different clusters. Such an operation may include finding amean or average trajectory of the clustered vehicle trajectories (e.g.,by averaging data representing the clustered vehicle trajectories) ineach cluster. In some embodiments, the target trajectory may beassociated with a single lane of the common road segment 1200.

The road model and/or sparse map may store trajectories associated witha road segment. These trajectories may be referred to as targettrajectories, which are provided to autonomous vehicles for autonomousnavigation. The target trajectories may be received from multiplevehicles, or may be generated based on actual trajectories orrecommended trajectories (actual trajectories with some modifications)received from multiple vehicles. The target trajectories included in theroad model or sparse map may be continuously updated (e.g., averaged)with new trajectories received from other vehicles.

Vehicles travelling on a road segment may collect data by varioussensors. The data may include landmarks, road signature profile, vehiclemotion (e.g., accelerometer data, speed data), vehicle position (e.g.,GPS data), and may either reconstruct the actual trajectoriesthemselves, or transmit the data to a server, which will reconstruct theactual trajectories for the vehicles. In some embodiments, the vehiclesmay transmit data relating to a trajectory (e.g., a curve in anarbitrary reference frame), landmarks data, and lane assignment alongtraveling path to server 1230. Various vehicles travelling along thesame road segment at multiple drives may have different trajectories.Server 1230 may identify routes or trajectories associated with eachlane from the trajectories received from vehicles through a clusteringprocess.

FIG. 22 illustrates a process of clustering vehicle trajectoriesassociated with vehicles 1205, 1210, 1215, 1220, and 1225 fordetermining a target trajectory for the common road segment (e.g., roadsegment 1200). The target trajectory or a plurality of targettrajectories determined from the clustering process may be included inthe autonomous vehicle road navigation model or sparse map 800. In someembodiments, vehicles 1205, 1210, 1215, 1220, and 1225 traveling alongroad segment 1200 may transmit a plurality of trajectories 2200 toserver 1230. In some embodiments, server 1230 may generate trajectoriesbased on landmark, road geometry, and vehicle motion informationreceived from vehicles 1205, 1210, 1215, 1220, and 1225. To generate theautonomous vehicle road navigation model, server 1230 may clustervehicle trajectories 1600 into a plurality of clusters 2205, 2210, 2215,2220, 2225, and 2230, as shown in FIG. 22 .

Clustering may be performed using various criteria. In some embodiments,all drives in a cluster may be similar with respect to the absoluteheading along the road segment 1200. The absolute heading may beobtained from GPS signals received by vehicles 1205, 1210, 1215, 1220,and 1225. In some embodiments, the absolute heading may be obtainedusing dead reckoning Dead reckoning, as one of skill in the art wouldunderstand, may be used to determine the current position and henceheading of vehicles 1205, 1210, 1215, 1220, and 1225 by using previouslydetermined position, estimated speed, etc. Trajectories clustered byabsolute heading may be useful for identifying routes along theroadways.

In some embodiments, all the drives in a cluster may be similar withrespect to the lane assignment (e.g., in the same lane before and aftera junction) along the drive on road segment 1200. Trajectories clusteredby lane assignment may be useful for identifying lanes along theroadways. In some embodiments, both criteria (e.g., absolute heading andlane assignment) may be used for clustering.

In each cluster 2205, 2210, 2215, 2220, 2225, and 2230, trajectories maybe averaged to obtain a target trajectory associated with the specificcluster. For example, the trajectories from multiple drives associatedwith the same lane cluster may be averaged. The averaged trajectory maybe a target trajectory associate with a specific lane. To average acluster of trajectories, server 1230 may select a reference frame of anarbitrary trajectory C0. For all other trajectories (C1, . . . , Cn),server 1230 may find a rigid transformation that maps C1 to C0, wherei=1, 2, . . . , n, where n is a positive integer number, correspondingto the total number of trajectories included in the cluster. Server 1230may compute a mean curve or trajectory in the C0 reference frame.

In some embodiments, the landmarks may define an arc length matchingbetween different drives, which may be used for alignment oftrajectories with lanes. In some embodiments, lane marks before andafter a junction may be used for alignment of trajectories with lanes.

To assemble lanes from the trajectories, server 1230 may select areference frame of an arbitrary lane. Server 1230 may map partiallyoverlapping lanes to the selected reference frame. Server 1230 maycontinue mapping until all lanes are in the same reference frame. Lanesthat are next to each other may be aligned as if they were the samelane, and later they may be shifted laterally.

Landmarks recognized along the road segment may be mapped to the commonreference frame, first at the lane level, then at the junction level.For example, the same landmarks may be recognized multiple times bymultiple vehicles in multiple drives. The data regarding the samelandmarks received in different drives may be slightly different. Suchdata may be averaged and mapped to the same reference frame, such as theC0 reference frame. Additionally or alternatively, the variance of thedata of the same landmark received in multiple drives may be calculated.

In some embodiments, each lane of road segment 120 may be associatedwith a target trajectory and certain landmarks. The target trajectory ora plurality of such target trajectories may be included in theautonomous vehicle road navigation model, which may be used later byother autonomous vehicles travelling along the same road segment 1200.Landmarks identified by vehicles 1205, 1210, 1215, 1220, and 1225 whilethe vehicles travel along road segment 1200 may be recorded inassociation with the target trajectory. The data of the targettrajectories and landmarks may be continuously or periodically updatedwith new data received from other vehicles in subsequent drives.

For localization of an autonomous vehicle, the disclosed systems andmethods may use an Extended Kalman Filter. The location of the vehiclemay be determined based on three dimensional position data and/or threedimensional orientation data, prediction of future location ahead ofvehicle's current location by integration of ego motion. Thelocalization of vehicle may be corrected or adjusted by imageobservations of landmarks. For example, when vehicle detects a landmarkwithin an image captured by the camera, the landmark may be compared toa known landmark stored within the road model or sparse map 800. Theknown landmark may have a known location (e.g., GPS data) along a targettrajectory stored in the road model and/or sparse map 800. Based on thecurrent speed and images of the landmark, the distance from the vehicleto the landmark may be estimated. The location of the vehicle along atarget trajectory may be adjusted based on the distance to the landmarkand the landmark's known location (stored in the road model or sparsemap 800). The landmark's position/location data (e.g., mean values frommultiple drives) stored in the road model and/or sparse map 800 may bepresumed to be accurate.

In some embodiments, the disclosed system may form a closed loopsubsystem, in which estimation of the vehicle six degrees of freedomlocation (e.g., three dimensional position data plus three dimensionalorientation data) may be used for navigating (e.g., steering the wheelof) the autonomous vehicle to reach a desired point (e.g., 1.3 secondahead in the stored). In turn, data measured from the steering andactual navigation may be used to estimate the six degrees of freedomlocation.

In some embodiments, poles along a road, such as lampposts and power orcable line poles may be used as landmarks for localizing the vehicles.Other landmarks such as traffic signs, traffic lights, arrows on theroad, stop lines, as well as static features or signatures of an objectalong the road segment may also be used as landmarks for localizing thevehicle. When poles are used for localization, the x observation of thepoles (i.e., the viewing angle from the vehicle) may be used, ratherthan the y observation (i.e., the distance to the pole) since thebottoms of the poles may be occluded and sometimes they are not on theroad plane.

FIG. 23 illustrates a navigation system for a vehicle, which may be usedfor autonomous navigation using a crowdsourced sparse map. Forillustration, the vehicle is referenced as vehicle 1205. The vehicleshown in FIG. 23 may be any other vehicle disclosed herein, including,for example, vehicles 1210, 1215, 1220, and 1225, as well as vehicle 200shown in other embodiments. As shown in FIG. 12 , vehicle 1205 maycommunicate with server 1230. Vehicle 1205 may include an image capturedevice 122 (e.g., camera 122). Vehicle 1205 may include a navigationsystem 2300 configured for providing navigation guidance for vehicle1205 to travel on a road (e.g., road segment 1200). Vehicle 1205 mayalso include other sensors, such as a speed sensor 2320 and anaccelerometer 2325. Speed sensor 2320 may be configured to detect thespeed of vehicle 1205. Accelerometer 2325 may be configured to detect anacceleration or deceleration of vehicle 1205. Vehicle 1205 shown in FIG.23 may be an autonomous vehicle, and the navigation system 2300 may beused for providing navigation guidance for autonomous driving.Alternatively, vehicle 1205 may also be a non-autonomous,human-controlled vehicle, and navigation system 2300 may still be usedfor providing navigation guidance.

Navigation system 2300 may include a communication unit 2305 configuredto communicate with server 1230 through communication path 1235.Navigation system 2300 may also include a GPS unit 2310 configured toreceive and process GPS signals. Navigation system 2300 may furtherinclude at least one processor 2315 configured to process data, such asGPS signals, map data from sparse map 800 (which may be stored on astorage device provided onboard vehicle 1205 and/or received from server1230), road geometry sensed by a road profile sensor 2330, imagescaptured by camera 122, and/or autonomous vehicle road navigation modelreceived from server 1230. The road profile sensor 2330 may includedifferent types of devices for measuring different types of roadprofile, such as road surface roughness, road width, road elevation,road curvature, etc. For example, the road profile sensor 2330 mayinclude a device that measures the motion of a suspension of vehicle2305 to derive the road roughness profile. In some embodiments, the roadprofile sensor 2330 may include radar sensors to measure the distancefrom vehicle 1205 to road sides (e.g., barrier on the road sides),thereby measuring the width of the road. In some embodiments, the roadprofile sensor 2330 may include a device configured for measuring the upand down elevation of the road. In some embodiment, the road profilesensor 2330 may include a device configured to measure the roadcurvature. For example, a camera (e.g., camera 122 or another camera)may be used to capture images of the road showing road curvatures.Vehicle 1205 may use such images to detect road curvatures.

The at least one processor 2315 may be programmed to receive, fromcamera 122, at least one environmental image associated with vehicle1205. The at least one processor 2315 may analyze the at least oneenvironmental image to determine navigation information related to thevehicle 1205. The navigation information may include a trajectoryrelated to the travel of vehicle 1205 along road segment 1200. The atleast one processor 2315 may determine the trajectory based on motionsof camera 122 (and hence the vehicle), such as three dimensionaltranslation and three dimensional rotational motions. In someembodiments, the at least one processor 2315 may determine thetranslation and rotational motions of camera 122 based on analysis of aplurality of images acquired by camera 122. In some embodiments, thenavigation information may include lane assignment information (e.g., inwhich lane vehicle 1205 is travelling along road segment 1200). Thenavigation information transmitted from vehicle 1205 to server 1230 maybe used by server 1230 to generate and/or update an autonomous vehicleroad navigation model, which may be transmitted back from server 1230 tovehicle 1205 for providing autonomous navigation guidance for vehicle1205.

The at least one processor 2315 may also be programmed to transmit thenavigation information from vehicle 1205 to server 1230. In someembodiments, the navigation information may be transmitted to server1230 along with road information. The road location information mayinclude at least one of the GPS signal received by the GPS unit 2310,landmark information, road geometry, lane information, etc. The at leastone processor 2315 may receive, from server 1230, the autonomous vehicleroad navigation model or a portion of the model. The autonomous vehicleroad navigation model received from server 1230 may include at least oneupdate based on the navigation information transmitted from vehicle 1205to server 1230. The portion of the model transmitted from server 1230 tovehicle 1205 may include an updated portion of the model. The at leastone processor 2315 may cause at least one navigational maneuver (e.g.,steering such as making a turn, braking, accelerating, passing anothervehicle, etc.) by vehicle 1205 based on the received autonomous vehicleroad navigation model or the updated portion of the model.

The at least one processor 2315 may be configured to communicate withvarious sensors and components included in vehicle 1205, includingcommunication unit 1705, GPS unit 2315, camera 122, speed sensor 2320,accelerometer 2325, and road profile sensor 2330. The at least oneprocessor 2315 may collect information or data from various sensors andcomponents, and transmit the information or data to server 1230 throughcommunication unit 2305. Alternatively or additionally, various sensorsor components of vehicle 1205 may also communicate with server 1230 andtransmit data or information collected by the sensors or components toserver 1230.

In some embodiments, vehicles 1205, 1210, 1215, 1220, and 1225 maycommunicate with each other, and may share navigation information witheach other, such that at least one of the vehicles 1205, 1210, 1215,1220, and 1225 may generate the autonomous vehicle road navigation modelusing crowdsourcing, e.g., based on information shared by othervehicles. In some embodiments, vehicles 1205, 1210, 1215, 1220, and 1225may share navigation information with each other and each vehicle mayupdate its own the autonomous vehicle road navigation model provided inthe vehicle. In some embodiments, at least one of the vehicles 1205,1210, 1215, 1220, and 1225 (e.g., vehicle 1205) may function as a hubvehicle. The at least one processor 2315 of the hub vehicle (e.g.,vehicle 1205) may perform some or all of the functions performed byserver 1230. For example, the at least one processor 2315 of the hubvehicle may communicate with other vehicles and receive navigationinformation from other vehicles. The at least one processor 2315 of thehub vehicle may generate the autonomous vehicle road navigation model oran update to the model based on the shared information received fromother vehicles. The at least one processor 2315 of the hub vehicle maytransmit the autonomous vehicle road navigation model or the update tothe model to other vehicles for providing autonomous navigationguidance.

Navigation Based on Sparse Maps

As previously discussed, the autonomous vehicle road navigation modelincluding sparse map 800 may include a plurality of mapped lane marksand a plurality of mapped objects/features associated with a roadsegment. As discussed in greater detail below, these mapped lane marks,objects, and features may be used when the autonomous vehicle navigates.For example, in some embodiments, the mapped objects and features may beused to localized a host vehicle relative to the map (e.g., relative toa mapped target trajectory). The mapped lane marks may be used (e.g., asa check) to determine a lateral position and/or orientation relative toa planned or target trajectory. With this position information, theautonomous vehicle may be able to adjust a heading direction to match adirection of a target trajectory at the determined position.

Vehicle 200 may be configured to detect lane marks in a given roadsegment. The road segment may include any markings on a road for guidingvehicle traffic on a roadway. For example, the lane marks may becontinuous or dashed lines demarking the edge of a lane of travel. Thelane marks may also include double lines, such as a double continuouslines, double dashed lines or a combination of continuous and dashedlines indicating, for example, whether passing is permitted in anadjacent lane. The lane marks may also include freeway entrance and exitmarkings indicating, for example, a deceleration lane for an exit rampor dotted lines indicating that a lane is turn-only or that the lane isending. The markings may further indicate a work zone, a temporary laneshift, a path of travel through an intersection, a median, a specialpurpose lane (e.g., a bike lane, HOV lane, etc.), or other miscellaneousmarkings (e.g., crosswalk, a speed hump, a railway crossing, a stopline, etc.).

Vehicle 200 may use cameras, such as image capture devices 122 and 124included in image acquisition unit 120, to capture images of thesurrounding lane marks. Vehicle 200 may analyze the images to detectpoint locations associated with the lane marks based on featuresidentified within one or more of the captured images. These pointlocations may be uploaded to a server to represent the lane marks insparse map 800. Depending on the position and field of view of thecamera, lane marks may be detected for both sides of the vehiclesimultaneously from a single image. In other embodiments, differentcameras may be used to capture images on multiple sides of the vehicle.Rather than uploading actual images of the lane marks, the marks may bestored in sparse map 800 as a spline or a series of points, thusreducing the size of sparse map 800 and/or the data that must beuploaded remotely by the vehicle.

FIGS. 24A-24D illustrate exemplary point locations that may be detectedby vehicle 200 to represent particular lane marks. Similar to thelandmarks described above, vehicle 200 may use various image recognitionalgorithms or software to identify point locations within a capturedimage. For example, vehicle 200 may recognize a series of edge points,corner points or various other point locations associated with aparticular lane mark. FIG. 24A shows a continuous lane mark 2410 thatmay be detected by vehicle 200. Lane mark 2410 may represent the outsideedge of a roadway, represented by a continuous white line. As shown inFIG. 24A, vehicle 200 may be configured to detect a plurality of edgelocation points 2411 along the lane mark. Location points 2411 may becollected to represent the lane mark at any intervals sufficient tocreate a mapped lane mark in the sparse map. For example, the lane markmay be represented by one point per meter of the detected edge, onepoint per every five meters of the detected edge, or at other suitablespacings. In some embodiments, the spacing may be determined by otherfactors, rather than at set intervals such as, for example, based onpoints where vehicle 200 has a highest confidence ranking of thelocation of the detected points. Although FIG. 24A shows edge locationpoints on an interior edge of lane mark 2410, points may be collected onthe outside edge of the line or along both edges. Further, while asingle line is shown in FIG. 24A, similar edge points may be detectedfor a double continuous line. For example, points 2411 may be detectedalong an edge of one or both of the continuous lines.

Vehicle 200 may also represent lane marks differently depending on thetype or shape of lane mark. FIG. 24B shows an exemplary dashed lane mark2420 that may be detected by vehicle 200. Rather than identifying edgepoints, as in FIG. 24A, vehicle may detect a series of corner points2421 representing corners of the lane dashes to define the full boundaryof the dash. While FIG. 24B shows each corner of a given dash markingbeing located, vehicle 200 may detect or upload a subset of the pointsshown in the figure. For example, vehicle 200 may detect the leadingedge or leading corner of a given dash mark, or may detect the twocorner points nearest the interior of the lane. Further, not every dashmark may be captured, for example, vehicle 200 may capture and/or recordpoints representing a sample of dash marks (e.g., every other, everythird, every fifth, etc.) or dash marks at a predefined spacing (e.g.,every meter, every five meters, every 10 meters, etc.) Corner points mayalso be detected for similar lane marks, such as markings showing a laneis for an exit ramp, that a particular lane is ending, or other variouslane marks that may have detectable corner points. Corner points mayalso be detected for lane marks consisting of double dashed lines or acombination of continuous and dashed lines.

In some embodiments, the points uploaded to the server to generate themapped lane marks may represent other points besides the detected edgepoints or corner points. FIG. 24C illustrates a series of points thatmay represent a centerline of a given lane mark. For example, continuouslane 2410 may be represented by centerline points 2441 along acenterline 2440 of the lane mark. In some embodiments, vehicle 200 maybe configured to detect these center points using various imagerecognition techniques, such as convolutional neural networks (CNN),scale-invariant feature transform (SIFT), histogram of orientedgradients (HOG) features, or other techniques. Alternatively, vehicle200 may detect other points, such as edge points 2411 shown in FIG. 24A,and may calculate centerline points 2441, for example, by detectingpoints along each edge and determining a midpoint between the edgepoints. Similarly, dashed lane mark 2420 may be represented bycenterline points 2451 along a centerline 2450 of the lane mark. Thecenterline points may be located at the edge of a dash, as shown in FIG.24C, or at various other locations along the centerline. For example,each dash may be represented by a single point in the geometric centerof the dash. The points may also be spaced at a predetermined intervalalong the centerline (e.g., every meter, 5 meters, 10 meters, etc.). Thecenterline points 2451 may be detected directly by vehicle 200, or maybe calculated based on other detected reference points, such as cornerpoints 2421, as shown in FIG. 24B. A centerline may also be used torepresent other lane mark types, such as a double line, using similartechniques as above.

In some embodiments, vehicle 200 may identify points representing otherfeatures, such as a vertex between two intersecting lane marks. FIG. 24Dshows exemplary points representing an intersection between two lanemarks 2460 and 2465. Vehicle 200 may calculate a vertex point 2466representing an intersection between the two lane marks. For example,one of lane marks 2460 or 2465 may represent a train crossing area orother crossing area in the road segment. While lane marks 2460 and 2465are shown as crossing each other perpendicularly, various otherconfigurations may be detected. For example, the lane marks 2460 and2465 may cross at other angles, or one or both of the lane marks mayterminate at the vertex point 2466. Similar techniques may also beapplied for intersections between dashed or other lane mark types. Inaddition to vertex point 2466, various other points 2467 may also bedetected, providing further information about the orientation of lanemarks 2460 and 2465.

Vehicle 200 may associate real-world coordinates with each detectedpoint of the lane mark. For example, location identifiers may begenerated, including coordinate for each point, to upload to a serverfor mapping the lane mark. The location identifiers may further includeother identifying information about the points, including whether thepoint represents a corner point, an edge point, center point, etc.Vehicle 200 may therefore be configured to determine a real-worldposition of each point based on analysis of the images. For example,vehicle 200 may detect other features in the image, such as the variouslandmarks described above, to locate the real-world position of the lanemarks. This may involve determining the location of the lane marks inthe image relative to the detected landmark or determining the positionof the vehicle based on the detected landmark and then determining adistance from the vehicle (or target trajectory of the vehicle) to thelane mark. When a landmark is not available, the location of the lanemark points may be determined relative to a position of the vehicledetermined based on dead reckoning. The real-world coordinates includedin the location identifiers may be represented as absolute coordinates(e.g., latitude/longitude coordinates), or may be relative to otherfeatures, such as based on a longitudinal position along a targettrajectory and a lateral distance from the target trajectory. Thelocation identifiers may then be uploaded to a server for generation ofthe mapped lane marks in the navigation model (such as sparse map 800).In some embodiments, the server may construct a spline representing thelane marks of a road segment. Alternatively, vehicle 200 may generatethe spline and upload it to the server to be recorded in thenavigational model.

FIG. 24E shows an exemplary navigation model or sparse map for acorresponding road segment that includes mapped lane marks. The sparsemap may include a target trajectory 2475 for a vehicle to follow along aroad segment. As described above, target trajectory 2475 may representan ideal path for a vehicle to take as it travels the corresponding roadsegment, or may be located elsewhere on the road (e.g., a centerline ofthe road, etc.). Target trajectory 2475 may be calculated in the variousmethods described above, for example, based on an aggregation (e.g., aweighted combination) of two or more reconstructed trajectories ofvehicles traversing the same road segment.

In some embodiments, the target trajectory may be generated equally forall vehicle types and for all road, vehicle, and/or environmentconditions. In other embodiments, however, various other factors orvariables may also be considered in generating the target trajectory. Adifferent target trajectory may be generated for different types ofvehicles (e.g., a private car, a light truck, and a full trailer). Forexample, a target trajectory with relatively tighter turning radii maybe generated for a small private car than a larger semi-trailer truck.In some embodiments, road, vehicle and environmental conditions may beconsidered as well. For example, a different target trajectory may begenerated for different road conditions (e.g., wet, snowy, icy, dry,etc.), vehicle conditions (e.g., tire condition or estimated tirecondition, brake condition or estimated brake condition, amount of fuelremaining, etc.) or environmental factors (e.g., time of day,visibility, weather, etc.). The target trajectory may also depend on oneor more aspects or features of a particular road segment (e.g., speedlimit, frequency and size of turns, grade, etc.). In some embodiments,various user settings may also be used to determine the targettrajectory, such as a set driving mode (e.g., desired drivingaggressiveness, economy mode, etc.).

The sparse map may also include mapped lane marks 2470 and 2480representing lane marks along the road segment. The mapped lane marksmay be represented by a plurality of location identifiers 2471 and 2481.As described above, the location identifiers may include locations inreal world coordinates of points associated with a detected lane mark.Similar to the target trajectory in the model, the lane marks may alsoinclude elevation data and may be represented as a curve inthree-dimensional space. For example, the curve may be a splineconnecting three dimensional polynomials of suitable order the curve maybe calculated based on the location identifiers. The mapped lane marksmay also include other information or metadata about the lane mark, suchas an identifier of the type of lane mark (e.g., between two lanes withthe same direction of travel, between two lanes of opposite direction oftravel, edge of a roadway, etc.) and/or other characteristics of thelane mark (e.g., continuous, dashed, single line, double line, yellow,white, etc.). In some embodiments, the mapped lane marks may becontinuously updated within the model, for example, using crowdsourcingtechniques. The same vehicle may upload location identifiers duringmultiple occasions of travelling the same road segment or data may beselected from a plurality of vehicles (such as 1205, 1210, 1215, 1220,and 1225) travelling the road segment at different times. Sparse map 800may then be updated or refined based on subsequent location identifiersreceived from the vehicles and stored in the system. As the mapped lanemarks are updated and refined, the updated road navigation model and/orsparse map may be distributed to a plurality of autonomous vehicles.

Generating the mapped lane marks in the sparse map may also includedetecting and/or mitigating errors based on anomalies in the images orin the actual lane marks themselves. FIG. 24F shows an exemplary anomaly2495 associated with detecting a lane mark 2490. Anomaly 2495 may appearin the image captured by vehicle 200, for example, from an objectobstructing the camera's view of the lane mark, debris on the lens, etc.In some instances, the anomaly may be due to the lane mark itself, whichmay be damaged or worn away, or partially covered, for example, by dirt,debris, water, snow or other materials on the road. Anomaly 2495 mayresult in an erroneous point 2491 being detected by vehicle 200. Sparsemap 800 may provide the correct the mapped lane mark and exclude theerror. In some embodiments, vehicle 200 may detect erroneous point 2491for example, by detecting anomaly 2495 in the image, or by identifyingthe error based on detected lane mark points before and after theanomaly. Based on detecting the anomaly, the vehicle may omit point 2491or may adjust it to be in line with other detected points. In otherembodiments, the error may be corrected after the point has beenuploaded, for example, by determining the point is outside of anexpected threshold based on other points uploaded during the same trip,or based on an aggregation of data from previous trips along the sameroad segment.

The mapped lane marks in the navigation model and/or sparse map may alsobe used for navigation by an autonomous vehicle traversing thecorresponding roadway. For example, a vehicle navigating along a targettrajectory may periodically use the mapped lane marks in the sparse mapto align itself with the target trajectory. As mentioned above, betweenlandmarks the vehicle may navigate based on dead reckoning in which thevehicle uses sensors to determine its ego motion and estimate itsposition relative to the target trajectory. Errors may accumulate overtime and vehicle's position determinations relative to the targettrajectory may become increasingly less accurate. Accordingly, thevehicle may use lane marks occurring in sparse map 800 (and their knownlocations) to reduce the dead reckoning-induced errors in positiondetermination. In this way, the identified lane marks included in sparsemap 800 may serve as navigational anchors from which an accurateposition of the vehicle relative to a target trajectory may bedetermined.

FIG. 25A shows an exemplary image 2500 of a vehicle's surroundingenvironment that may be used for navigation based on the mapped lanemarks. Image 2500 may be captured, for example, by vehicle 200 throughimage capture devices 122 and 124 included in image acquisition unit120. Image 2500 may include an image of at least one lane mark 2510, asshown in FIG. 25A. Image 2500 may also include one or more landmarks2521, such as road sign, used for navigation as described above. Someelements shown in FIG. 25A, such as elements 2511, 2530, and 2520 whichdo not appear in the captured image 2500 but are detected and/ordetermined by vehicle 200 are also shown for reference.

Using the various techniques described above with respect to FIGS. 24A-Dand 24F, a vehicle may analyze image 2500 to identify lane mark 2510.Various points 2511 may be detected corresponding to features of thelane mark in the image. Points 2511, for example, may correspond to anedge of the lane mark, a corner of the lane mark, a midpoint of the lanemark, a vertex between two intersecting lane marks, or various otherfeatures or locations. Points 2511 may be detected to correspond to alocation of points stored in a navigation model received from a server.For example, if a sparse map is received containing points thatrepresent a centerline of a mapped lane mark, points 2511 may also bedetected based on a centerline of lane mark 2510.

The vehicle may also determine a longitudinal position represented byelement 2520 and located along a target trajectory. Longitudinalposition 2520 may be determined from image 2500, for example, bydetecting landmark 2521 within image 2500 and comparing a measuredlocation to a known landmark location stored in the road model or sparsemap 800. The location of the vehicle along a target trajectory may thenbe determined based on the distance to the landmark and the landmark'sknown location. The longitudinal position 2520 may also be determinedfrom images other than those used to determine the position of a lanemark. For example, longitudinal position 2520 may be determined bydetecting landmarks in images from other cameras within imageacquisition unit 120 taken simultaneously or near simultaneously toimage 2500. In some instances, the vehicle may not be near any landmarksor other reference points for determining longitudinal position 2520. Insuch instances, the vehicle may be navigating based on dead reckoningand thus may use sensors to determine its ego motion and estimate alongitudinal position 2520 relative to the target trajectory. Thevehicle may also determine a distance 2530 representing the actualdistance between the vehicle and lane mark 2510 observed in the capturedimage(s). The camera angle, the speed of the vehicle, the width of thevehicle, or various other factors may be accounted for in determiningdistance 2530.

FIG. 25B illustrates a lateral localization correction of the vehiclebased on the mapped lane marks in a road navigation model. As describedabove, vehicle 200 may determine a distance 2530 between vehicle 200 anda lane mark 2510 using one or more images captured by vehicle 200.Vehicle 200 may also have access to a road navigation model, such assparse map 800, which may include a mapped lane mark 2550 and a targettrajectory 2555. Mapped lane mark 2550 may be modeled using thetechniques described above, for example using crowdsourced locationidentifiers captured by a plurality of vehicles. Target trajectory 2555may also be generated using the various techniques described previously.Vehicle 200 may also determine or estimate a longitudinal position 2520along target trajectory 2555 as described above with respect to FIG.25A. Vehicle 200 may then determine an expected distance 2540 based on alateral distance between target trajectory 2555 and mapped lane mark2550 corresponding to longitudinal position 2520. The laterallocalization of vehicle 200 may be corrected or adjusted by comparingthe actual distance 2530, measured using the captured image(s), with theexpected distance 2540 from the model.

FIGS. 25C and 25D provide illustrations associated with another examplefor localizing a host vehicle during navigation based on mappedlandmarks/objects/features in a sparse map. FIG. 25C conceptuallyrepresents a series of images captured from a vehicle navigating along aroad segment 2560. In this example, road segment 2560 includes astraight section of a two-lane divided highway delineated by road edges2561 and 2562 and center lane marking 2563. As shown, the host vehicleis navigating along a lane 2564, which is associated with a mappedtarget trajectory 2565. Thus, in an ideal situation (and withoutinfluencers such as the presence of target vehicles or objects in theroadway, etc.) the host vehicle should closely track the mapped targettrajectory 2565 as it navigates along lane 2564 of road segment 2560. Inreality, the host vehicle may experience drift as it navigates alongmapped target trajectory 2565. For effective and safe navigation, thisdrift should be maintained within acceptable limits (e.g., +/−10 cm oflateral displacement from target trajectory 2565 or any other suitablethreshold). To periodically account for drift and to make any neededcourse corrections to ensure that the host vehicle follows targettrajectory 2565, the disclosed navigation systems may be able tolocalize the host vehicle along the target trajectory 2565 (e.g.,determine a lateral and longitudinal position of the host vehiclerelative to the target trajectory 2565) using one or more mappedfeatures/objects included in the sparse map.

As a simple example, FIG. 25C shows a speed limit sign 2566 as it mayappear in five different, sequentially captured images as the hostvehicle navigates along road segment 2560. For example, at a first time,t₀, sign 2566 may appear in a captured image near the horizon. As thehost vehicle approaches sign 2566, in subsequentially captured images attimes t₁, t₂, t₃, and t₄, sign 2566 will appear at different 2D X-Ypixel locations of the captured images. For example, in the capturedimage space, sign 2566 will move downward and to the right along curve2567 (e.g., a curve extending through the center of the sign in each ofthe five captured image frames). Sign 2566 will also appear to increasein size as it is approached by the host vehicle (i.e., it will occupy agreat number of pixels in subsequently captured images).

These changes in the image space representations of an object, such assign 2566, may be exploited to determine a localized position of thehost vehicle along a target trajectory. For example, as described in thepresent disclosure, any detectable object or feature, such as a semanticfeature like sign 2566 or a detectable non-semantic feature, may beidentified by one or more harvesting vehicles that previously traverseda road segment (e.g., road segment 2560). A mapping server may collectthe harvested drive information from a plurality of vehicles, aggregateand correlate that information, and generate a sparse map including, forexample, a target trajectory 2565 for lane 2564 of road segment 2560.The sparse map may also store a location of sign 2566 (along with typeinformation, etc.). During navigation (e.g., prior to entering roadsegment 2560), a host vehicle may be supplied with a map tile includinga sparse map for road segment 2560. To navigate in lane 2564 of roadsegment 2560, the host vehicle may follow mapped target trajectory 2565.

The mapped representation of sign 2566 may be used by the host vehicleto localize itself relative to the target trajectory. For example, acamera on the host vehicle will capture an image 2570 of the environmentof the host vehicle, and that captured image 2570 may include an imagerepresentation of sign 2566 having a certain size and a certain X-Yimage location, as shown in FIG. 25D. This size and X-Y image locationcan be used to determine the host vehicle's position relative to targettrajectory 2565. For example, based on the sparse map including arepresentation of sign 2566, a navigation processor of the host vehiclecan determine that in response to the host vehicle traveling alongtarget trajectory 2565, a representation of sign 2566 should appear incaptured images such that a center of sign 2566 will move (in imagespace) along line 2567. If a captured image, such as image 2570, showsthe center (or other reference point) displaced from line 2567 (e.g.,the expected image space trajectory), then the host vehicle navigationsystem can determine that at the time of the captured image it was notlocated on target trajectory 2565. From the image, however, thenavigation processor can determine an appropriate navigationalcorrection to return the host vehicle to the target trajectory 2565. Forexample, if analysis shows an image location of sign 2566 that isdisplaced in the image by a distance 2572 to the left of the expectedimage space location on line 2567, then the navigation processor maycause a heading change by the host vehicle (e.g., change the steeringangle of the wheels) to move the host vehicle leftward by a distance2573. In this way, each captured image can be used as part of a feedbackloop process such that a difference between an observed image positionof sign 2566 and expected image trajectory 2567 may be minimized toensure that the host vehicle continues along target trajectory 2565 withlittle to no deviation. Of course, the more mapped objects that areavailable, the more often the described localization technique may beemployed, which can reduce or eliminate drift-induced deviations fromtarget trajectory 2565.

The process described above may be useful for detecting a lateralorientation or displacement of the host vehicle relative to a targettrajectory. Localization of the host vehicle relative to targettrajectory 2565 may also include a determination of a longitudinallocation of the target vehicle along the target trajectory. For example,captured image 2570 includes a representation of sign 2566 as having acertain image size (e.g., 2D X-Y pixel area). This size can be comparedto an expected image size of mapped sign 2566 as it travels throughimage space along line 2567 (e.g., as the size of the sign progressivelyincreases, as shown in FIG. 25C). Based on the image size of sign 2566in image 2570, and based on the expected size progression in image spacerelative to mapped target trajectory 2565, the host vehicle candetermine its longitudinal position (at the time when image 2570 wascaptured) relative to target trajectory 2565. This longitudinal positioncoupled with any lateral displacement relative to target trajectory2565, as described above, allows for full localization of the hostvehicle relative to target trajectory 2565, as the host vehiclenavigates along road 2560.

FIGS. 25C and 25D provide just one example of the disclosed localizationtechnique using a single mapped object and a single target trajectory.In other examples, there may be many more target trajectories (e.g., onetarget trajectory for each viable lane of a multi-lane highway, urbanstreet, complex junction, etc.) and there may be many more mappedavailable for localization. For example, a sparse map representative ofan urban environment may include many objects per meter available forlocalization.

FIG. 26A is a flowchart showing an exemplary process 2600A for mapping alane mark for use in autonomous vehicle navigation, consistent withdisclosed embodiments. At step 2610, process 2600A may include receivingtwo or more location identifiers associated with a detected lane mark.For example, step 2610 may be performed by server 1230 or one or moreprocessors associated with the server. The location identifiers mayinclude locations in real-world coordinates of points associated withthe detected lane mark, as described above with respect to FIG. 24E. Insome embodiments, the location identifiers may also contain other data,such as additional information about the road segment or the lane mark.Additional data may also be received during step 2610, such asaccelerometer data, speed data, landmarks data, road geometry or profiledata, vehicle positioning data, ego motion data, or various other formsof data described above. The location identifiers may be generated by avehicle, such as vehicles 1205, 1210, 1215, 1220, and 1225, based onimages captured by the vehicle. For example, the identifiers may bedetermined based on acquisition, from a camera associated with a hostvehicle, of at least one image representative of an environment of thehost vehicle, analysis of the at least one image to detect the lane markin the environment of the host vehicle, and analysis of the at least oneimage to determine a position of the detected lane mark relative to alocation associated with the host vehicle. As described above, the lanemark may include a variety of different marking types, and the locationidentifiers may correspond to a variety of points relative to the lanemark. For example, where the detected lane mark is part of a dashed linemarking a lane boundary, the points may correspond to detected cornersof the lane mark. Where the detected lane mark is part of a continuousline marking a lane boundary, the points may correspond to a detectededge of the lane mark, with various spacings as described above. In someembodiments, the points may correspond to the centerline of the detectedlane mark, as shown in FIG. 24C, or may correspond to a vertex betweentwo intersecting lane marks and at least one two other points associatedwith the intersecting lane marks, as shown in FIG. 24D.

At step 2612, process 2600A may include associating the detected lanemark with a corresponding road segment. For example, server 1230 mayanalyze the real-world coordinates, or other information received duringstep 2610, and compare the coordinates or other information to locationinformation stored in an autonomous vehicle road navigation model.Server 1230 may determine a road segment in the model that correspondsto the real-world road segment where the lane mark was detected.

At step 2614, process 2600A may include updating an autonomous vehicleroad navigation model relative to the corresponding road segment basedon the two or more location identifiers associated with the detectedlane mark. For example, the autonomous road navigation model may besparse map 800, and server 1230 may update the sparse map to include oradjust a mapped lane mark in the model. Server 1230 may update the modelbased on the various methods or processes described above with respectto FIG. 24E. In some embodiments, updating the autonomous vehicle roadnavigation model may include storing one or more indicators of positionin real world coordinates of the detected lane mark. The autonomousvehicle road navigation model may also include a at least one targettrajectory for a vehicle to follow along the corresponding road segment,as shown in FIG. 24E.

At step 2616, process 2600A may include distributing the updatedautonomous vehicle road navigation model to a plurality of autonomousvehicles. For example, server 1230 may distribute the updated autonomousvehicle road navigation model to vehicles 1205, 1210, 1215, 1220, and1225, which may use the model for navigation. The autonomous vehicleroad navigation model may be distributed via one or more networks (e.g.,over a cellular network and/or the Internet, etc.), through wirelesscommunication paths 1235, as shown in FIG. 12 .

In some embodiments, the lane marks may be mapped using data receivedfrom a plurality of vehicles, such as through a crowdsourcing technique,as described above with respect to FIG. 24E. For example, process 2600Amay include receiving a first communication from a first host vehicle,including location identifiers associated with a detected lane mark, andreceiving a second communication from a second host vehicle, includingadditional location identifiers associated with the detected lane mark.For example, the second communication may be received from a subsequentvehicle travelling on the same road segment, or from the same vehicle ona subsequent trip along the same road segment. Process 2600A may furtherinclude refining a determination of at least one position associatedwith the detected lane mark based on the location identifiers receivedin the first communication and based on the additional locationidentifiers received in the second communication. This may include usingan average of the multiple location identifiers and/or filtering out“ghost” identifiers that may not reflect the real-world position of thelane mark.

FIG. 26B is a flowchart showing an exemplary process 2600B forautonomously navigating a host vehicle along a road segment using mappedlane marks. Process 2600B may be performed, for example, by processingunit 110 of autonomous vehicle 200. At step 2620, process 2600B mayinclude receiving from a server-based system an autonomous vehicle roadnavigation model. In some embodiments, the autonomous vehicle roadnavigation model may include a target trajectory for the host vehiclealong the road segment and location identifiers associated with one ormore lane marks associated with the road segment. For example, vehicle200 may receive sparse map 800 or another road navigation modeldeveloped using process 2600A. In some embodiments, the targettrajectory may be represented as a three-dimensional spline, forexample, as shown in FIG. 9B. As described above with respect to FIGS.24A-F, the location identifiers may include locations in real worldcoordinates of points associated with the lane mark (e.g., corner pointsof a dashed lane mark, edge points of a continuous lane mark, a vertexbetween two intersecting lane marks and other points associated with theintersecting lane marks, a centerline associated with the lane mark,etc.).

At step 2621, process 2600B may include receiving at least one imagerepresentative of an environment of the vehicle. The image may bereceived from an image capture device of the vehicle, such as throughimage capture devices 122 and 124 included in image acquisition unit120. The image may include an image of one or more lane marks, similarto image 2500 described above.

At step 2622, process 2600B may include determining a longitudinalposition of the host vehicle along the target trajectory. As describedabove with respect to FIG. 25A, this may be based on other informationin the captured image (e.g., landmarks, etc.) or by dead reckoning ofthe vehicle between detected landmarks.

At step 2623, process 2600B may include determining an expected lateraldistance to the lane mark based on the determined longitudinal positionof the host vehicle along the target trajectory and based on the two ormore location identifiers associated with the at least one lane mark.For example, vehicle 200 may use sparse map 800 to determine an expectedlateral distance to the lane mark. As shown in FIG. 25B, longitudinalposition 2520 along a target trajectory 2555 may be determined in step2622. Using spare map 800, vehicle 200 may determine an expecteddistance 2540 to mapped lane mark 2550 corresponding to longitudinalposition 2520.

At step 2624, process 2600B may include analyzing the at least one imageto identify the at least one lane mark. Vehicle 200, for example, mayuse various image recognition techniques or algorithms to identify thelane mark within the image, as described above. For example, lane mark2510 may be detected through image analysis of image 2500, as shown inFIG. 25A.

At step 2625, process 2600B may include determining an actual lateraldistance to the at least one lane mark based on analysis of the at leastone image. For example, the vehicle may determine a distance 2530, asshown in FIG. 25A, representing the actual distance between the vehicleand lane mark 2510. The camera angle, the speed of the vehicle, thewidth of the vehicle, the position of the camera relative to thevehicle, or various other factors may be accounted for in determiningdistance 2530.

At step 2626, process 2600B may include determining an autonomoussteering action for the host vehicle based on a difference between theexpected lateral distance to the at least one lane mark and thedetermined actual lateral distance to the at least one lane mark. Forexample, as described above with respect to FIG. 25B, vehicle 200 maycompare actual distance 2530 with an expected distance 2540. Thedifference between the actual and expected distance may indicate anerror (and its magnitude) between the vehicle's actual position and thetarget trajectory to be followed by the vehicle. Accordingly, thevehicle may determine an autonomous steering action or other autonomousaction based on the difference. For example, if actual distance 2530 isless than expected distance 2540, as shown in FIG. 25B, the vehicle maydetermine an autonomous steering action to direct the vehicle left, awayfrom lane mark 2510. Thus, the vehicle's position relative to the targettrajectory may be corrected. Process 2600B may be used, for example, toimprove navigation of the vehicle between landmarks.

Processes 2600A and 2600B provide examples only of techniques that maybe used for navigating a host vehicle using the disclosed sparse maps.In other examples, processes consistent with those described relative toFIGS. 25C and 25D may also be employed.

Ego Motion Correction of LIDAR Output

As described elsewhere in this disclosure, a vehicle or a driver maynavigate a vehicle along a road segment in the environment. The vehiclemay collect various types of information related to the road. Forexample, the vehicle may be equipped with a LIDAR system to collectLIDAR reflections from one or more objects from its environment and/orone or more cameras to capture images from the environment. Because ofthe host vehicle's own movement, a non-moving object (e.g., a lightpole) may move in the field of view of the LIDAR system, which mayappear in the collected data (e.g., a point cloud generated based onreflections of the laser emissions by the object) as a moving objecteven if the object itself does not move. As such, in some instances, incomplex, cluttered scenes, small objects and slow moving objects may bedifficult to detect. Also, a traditional LIDAR system may mis-identifysmaller objects as moving objects. Similarly, a traditional LIDAR systemmay mis-identify a moving object (e.g., a target vehicle) that is movingalong with the host vehicle as a non-moving object. Therefore, it may bedesirable to reduce or eliminate the possibility of misidentification ofa non-moving object as a moving object (or vice versa). This disclosuredescribes systems and methods that may correlate LIDAR points across twoor more frames and remove the depth effects caused by the ego motion ofthe host vehicle. After the effects caused by the ego motion areremoved, static objects (e.g., non-moving background objects) may showno velocity (i.e., the velocity thereof equals zero), and moving objectsmay be identified as those having points that include a velocity greaterthan zero.

This disclosure provides, for example, a system that may determine atleast one indicator of ego motion of the host vehicle. The ego motion ofthe host vehicle may refer to any environmental displacement of the hostvehicle with respect to a non-moving reference point or object. Forexample, as described elsewhere in this disclosure, the ego motion ofthe camera (and hence the vehicle body) may be estimated based on anoptical flow analysis of captured images. An optical flow analysis of asequence of images identifies movement of pixels from the sequence ofimages, and based on the identified movement, determines motions of thevehicle. The system may also be configured to receive, from a LIDARsystem associated with the host vehicle and based on a first LIDAR scanof a field of view of the LIDAR system, a first point cloud at, forexample, a first time point. The first point cloud may include a firstrepresentation of at least a portion of an object. The system mayfurther be configured to receive, from the LIDAR system and based on asecond LIDAR scan of the field of view of the LIDAR system, a secondpoint cloud at, for example, a second time point. The second point cloudmay include a second representation of the at least a portion of theobject. The system may also determine a velocity of the object based onthe at least one indicator of ego motion of the host vehicle, and basedon a comparison of the first point cloud, including the firstrepresentation of the at least a portion of the object, and the secondpoint cloud, including the second representation of the at least aportion of the object.

FIG. 27 illustrates an exemplary system 2700 for detecting one or moreobjects in the environment of the host vehicle consistent with disclosedembodiments. As illustrated in FIG. 27 , system 2700 may include aserver 2710, one or more vehicles 2720 (e.g., vehicle 2720 a, vehicle2720 b, . . . , vehicle 2720 n), a network 2730, and a database 2740.

A vehicle 2720 may collect information from its environment and transmitthe collected information to server 2710 via, for example, network 2730.For example, vehicle 2720 may include one or more sensors configured tocollect data and information from its environment. Vehicle 2720 maytransmit the data and information (or the derived data therefrom) toserver 2710. By way of example, vehicle 2720 may include an image sensor(e.g., a camera) configured to capture one or more images of itsenvironment. As another example, vehicle 2720 may include a LIDAR systemconfigured to gather LIDAR reflection information within a 360-degreefield of view around vehicle 2720 or from any sub-segment of the360-degree field of view (e.g., one or more FOVs each representing lessthan 360 degrees). In some embodiments, vehicle 2720 may include a LIDARsystem and one or more cameras.

Server 2710 may process data and/or information received from one ormore vehicles 2720. For example, server 2710 may receive from a vehicle2720 information relating to an object (e.g., the location of theobject). Server 2710 may update a map to add the object into the map (orremove the object from the map). In some embodiments, server 2710 maytransmit the updated map (or at least a portion thereof) to one or morevehicles 2720.

While FIG. 27 illustrates one server 2710, one skilled in the art wouldunderstand that system 300 may include one or more servers 2710 that,individually or in combination, perform the functions of server 2710disclosed in this application. For example, server 2710 may constitute acloud server group comprising two or more servers that perform thefunctions disclosed herein. The term “cloud server” refers to a computerplatform that provides services via a network, such as the Internet. Inthis example configuration, server 2710 may use virtual machines thatmay not correspond to individual hardware. For example, computationaland/or storage capabilities may be implemented by allocating appropriateportions of computation/storage power from a scalable repository, suchas a data center or a distributed computing environment. In one example,server 2710 may implement the methods described herein using customizedhard-wired logic, one or more Application Specific Integrated Circuits(ASICs) or Field Programmable Gate Arrays (FPGAs), firmware, and/orprogram logic which, in combination with the computer system, causeserver 2710 to be a special-purpose machine.

Network 2730 may be configured to facilitate communications among thecomponents of system 2700. Network 2730 may include wired and wirelesscommunication networks, such as a local-area network (LAN), a wide-areanetwork (WAN), a computer network, a wireless network, atelecommunications network, or the like, or a combination thereof.

Database 2740 may be configured to store information and data for one ormore components of system 2700. For example, database 2740 may store thedata (e.g., map data) for server 2710. One or more vehicles 2720 mayobtain the map data stored in database 2740 via, for example, network2730.

FIG. 28 is a block diagram of an exemplary server 2710 consistent withthe disclosed embodiments. As illustrated in FIG. 28 , server 2710 mayinclude at least one processor (e.g., processor 2801), a memory 2802, atleast one storage device (e.g., storage device 2803), a communicationsport 2804, and an I/O device 2805.

Processor 2801 may be configured to perform one or more functions ofserver 2710 described in this disclosure. Processor 2801 may include amicroprocessor, preprocessors (such as an image preprocessor), agraphics processing unit (GPU), a central processing unit (CPU), supportcircuits, digital signal processors, integrated circuits, memory, or anyother types of devices suitable for running applications or performing acomputing task. In some embodiments, processor 2801 may include any typeof single or multi-core processor, mobile device microcontroller,central processing unit, etc. Various processing devices may be used,including, for example, processors available from manufacturers such asIntel®, AMD®, etc., or GPUs available from manufacturers such asNVIDIA®, ATI®, etc. and may include various architectures (e.g., x86processor, ARM®, etc.). Any of the processing devices disclosed hereinmay be configured to perform certain functions. Configuring a processingdevice, such as any of the described processors or other controller ormicroprocessor, to perform certain functions may include programming ofcomputer-executable instructions and making those instructions availableto the processing device for execution during operation of theprocessing device. In some embodiments, configuring a processing devicemay include programming the processing device directly witharchitectural instructions. For example, processing devices such asfield-programmable gate arrays (FPGAs), application-specific integratedcircuits (ASICs), and the like may be configured using, for example, oneor more hardware description languages (HDLs).

Server 2710 may also include a memory 2802 that may store instructionsfor various components of server 2710. For example, memory 2802 maystore instructions that, when executed by processor 2801, may beconfigured to cause processor 2801 to perform one or more functionsdescribed herein. Memory 2802 may include any number of random-accessmemories, read-only memories, flash memories, disk drives, opticalstorage, tape storage, removable storage, and other types of storage. Inone instance, memory 2802 may be separate from processor 2801. Inanother instance, memory 2802 may be integrated into processor 2801.

Storage device 2803 may be configured to store various data andinformation for one or more components of server 2710. For example,storage device 2803 may store map data. Server 2710 may update the mapdata based on the data and/or information received from one or morevehicles 2720. Server 2710 may also store the updated map data intostorage device 2803. Storage device 2803 may include one or more harddrives, tapes, one or more solid-state drives, any device suitable forwriting and read data, or the like, or a combination thereof.

Communications port 2804 may be configured to facilitate datacommunications between server 2710 and one or more components of system2700 via network 2730. For example, communications port 2804 may beconfigured to receive data from and transmit data to one or morecomponents of system 100 via one or more public or private networks,including the Internet, an Intranet, a WAN (Wide-Area Network), a MAN(Metropolitan-Area Network), a wireless network compliant with the IEEE802.11a/b/g/n Standards, a leased line, or the like.

I/O device 2805 may be configured to receive input from the user ofserver 2710, and one or more components of server 2710 may perform oneor more functions in response to the input received. In someembodiments, I/O device 2805 may include an interface displayed on atouchscreen. I/O device 2805 may also be configured to outputinformation and/or data to the user. For example, I/O device 2805 mayinclude a display configured to display map data.

FIG. 29 is a block diagram of an exemplary vehicle 2720 consistent withthe disclosed embodiments. As illustrated in FIG. 29 , vehicle 2720 mayinclude at least one processor (e.g., processor 2901), a memory 2902, atleast one storage device (e.g., storage device 2903), a communicationsport 2904, an I/O device 2905, one or more sensors 2906, a LIDAR system2907, and a navigation system 2908.

Processor 2901 may be configured to perform one or more functions ofvehicle 2720 described in this disclosure. Processor 2901 may include amicroprocessor, preprocessors (such as an image preprocessor), agraphics processing unit (GPU), a central processing unit (CPU), supportcircuits, digital signal processors, integrated circuits, memory, or anyother types of devices suitable for running applications or performing acomputing task. In some embodiments, processor 2901 may include any typeof single or multi-core processor, mobile device microcontroller,central processing unit, etc. Various processing devices may be used,including, for example, processors available from manufacturers such asIntel®, AMD®, etc., or GPUs available from manufacturers such asNVIDIA®, ATI®, etc. and may include various architectures (e.g., x86processor, ARM®, etc.). Any of the processing devices disclosed hereinmay be configured to perform certain functions. Configuring a processingdevice, such as any of the described processors or other controller ormicroprocessor, to perform certain functions may include programming ofcomputer-executable instructions and making those instructions availableto the processing device for execution during operation of theprocessing device. In some embodiments, configuring a processing devicemay include programming the processing device directly witharchitectural instructions. For example, processing devices such asfield-programmable gate arrays (FPGAs), application-specific integratedcircuits (ASICs), and the like may be configured using, for example, oneor more hardware description languages (HDLs).

Vehicle 2720 may also include a memory 2902 that may store instructionsfor various components of server 2710. For example, memory 2902 maystore instructions that, when executed by processor 2901, may beconfigured to cause processor 2901 to perform one or more functionsdescribed herein. Memory 2902 may include any number of random-accessmemories, read-only memories, flash memories, disk drives, opticalstorage, tape storage, removable storage, and other types of storage. Inone instance, memory 2902 may be separate from processor 2901. Inanother instance, memory 2902 may be integrated into processor 2901. Insome embodiments, memory 2902 may include software for performing one ormore computing tasks, as well as a trained system, such as a neuralnetwork, or a deep neural network.

Storage device 2903 may be configured to store various data andinformation for one or more components of vehicle 2720. Storage device2903 may include one or more hard drives, tapes, one or more solid-statedrives, any device suitable for writing and read data, or the like, or acombination thereof.

Communications port 2904 may be configured to facilitate datacommunications between vehicle 2720 and one or more components of system2700 via network 2730. For example, communications port 2904 may beconfigured to receive data from and transmit data to server 2710 via oneor more public or private networks, including the Internet, an Intranet,a WAN (Wide-Area Network), a MAN (Metropolitan-Area Network), a wirelessnetwork compliant with the IEEE 802.11a/b/g/n Standards, a leased line,or the like.

I/O device 2905 may be configured to receive input from the user ofserver 2710, and one or more components of server 2710 may perform oneor more functions in response to the input received. In someembodiments, I/O device 2905 may include an interface displayed on atouchscreen. I/O device 2905 may also be configured to outputinformation and/or data to the user. For example, I/O device 2905 mayinclude a display configured to display a map. In some embodiments,vehicle 2720 may receive data of the map (or at least a portion thereof)from server 2710 via, for example, network 2730.

Sensor 2906 may be configured to collect information relating to vehicle2720 and/or the environment of vehicle 2720. Sensor 2906 may include oneor more of an image sensor (e.g., a camera), a positioning device (e.g.,a Global Positioning System (GPS) device), an accelerometer, a gyrosensor, a speedometer, or the like, or a combination thereof. Forexample, vehicle 2720 may include an image sensor (e.g., a camera)configured to capture one or more images of its environment, which mayinclude representation of an object (or at least a portion thereof). Asanother example, vehicle 2720 may include a GPS device configured tocollect positioning data associated with positions of vehicle 2720 overa period of time.

LIDAR system 2907 may include one or more LIDAR units. In someembodiments, the one or more LIDAR units may be positioned on a roof ofvehicle 2720. Such a unit may include a rotating unit configured togather LIDAR reflection information within a 360-degree field of viewaround vehicle 2720 or from any sub-segment of the 360-degree field ofview (e.g., one or more FOVs each representing less than 360 degrees).In some embodiments, a LIDAR unit may be positioned at a forwardlocation on vehicle 2720 (e.g., near the headlights, in the front grill,near the fog lamps, in a forward bumper, or at any other suitablelocation). In some cases, one or more LIDAR units installed on a forwardportion of vehicle 2720 may collect reflection information from a fieldof view in an environment forward of vehicle 2720. The data collected byLIDAR system 2907 may be provided to processor 2901. Alternatively oradditionally, the data may be transmitted to server 2710 and/or database2740 via network 2730.

Any suitable type of LIDAR unit may be included on vehicle 2720. In somecases, LIDAR system 2907 may include one or more flash LIDAR units(e.g., 3D flash LIDAR) where an entire LIDAR field of view (FOV) isilluminated with a single laser pulse, and a sensor including rows andcolumns of pixels to record returned light intensity and time offlight/depth information. Such flash systems may illuminate a scene andcollect LIDAR “images” multiple times per second. Scanning LIDAR unitsmay also be employed. Such scanning LIDAR units may rely on one or moretechniques for dispersing a laser beam over a particular FOV. In somecases, a scanning LIDAR unit may include a scanning mirror that deflectsand directs a laser beam toward objects within the FOV Scanning mirrorsmay rotate through a full 360 degrees or may rotate along a single axisor multiple axes over less than 360 degrees to direct the laser toward apredetermined FOV. In some cases, LIDAR units may scan one horizontalline. In other cases, a LIDAR unit may scan multiple horizontal lineswithin an FOV, effectively rastering a particular FOV multiple times persecond.

The LIDAR units in LIDAR system 2907 may include any suitable lasersource. In some embodiments, the LIDAR units may employ a continuouslaser. In other cases, the LIDAR units may rely upon pulsed laseremissions. Additionally, any suitable laser wavelength may be employed.In some cases, a wavelength of between about 600 nm to about 1000 nm maybe used.

The LIDAR unit(s) in LIDAR system 2907 may also include any suitabletype of sensor and provide any suitable type of output. In some cases,sensors of the LIDAR units may include solid state photodetectors, suchas one or more photodiodes or photomultipliers. The sensors may alsoinclude one or more CMOS or CCD devices including any number of pixels.These sensors may be sensitive to laser light reflected from a scenewithin the LIDAR FOV. The sensors may enable various types of outputfrom a LIDAR unit. In some cases, a LIDAR unit may output raw lightintensity values and time of flight information representative of thereflected laser light collected at each sensor or at each pixel orsub-component of a particular sensor. Additionally or alternatively, aLIDAR unit may output a point cloud (e.g., a 3D point cloud) that mayinclude light intensity and depth/distance information relative to eachcollected point). LIDAR units may also output various types of depthmaps representative of light reflection amplitude and distance to pointswithin a field of view. LIDAR units may provide depth or distanceinformation relative to particular points within an FOV by noting a timeat which light from the LIDAR's light source was initially projectedtoward the FOV and recording a time at which the incident laser light isreceived by a sensor in the LIDAR unit. The time difference mayrepresent a time of flight, which may be directly related to the roundtrip distance that the incident laser light traveled from the lasersource to a reflecting object and back to the LIDAR unit. Monitoring thetime of flight information associated with individual laser spots orsmall segments of a LIDAR FOV may provide accurate distance informationfor a plurality of points within the FOV (e.g., mapping to even verysmall features of objects within the FOV). In some cases, LIDAR unitsmay output more complex information, such as classification informationthat correlates one or more laser reflections with a type of object fromwhich the laser reflection was acquired.

Navigation system 2908 may be configured to assist a driver of vehicle2720 to operate vehicle 2720. For example, navigation system 2908 maygenerate an alert when an object (e.g., another vehicle) is within apredetermined distance from the body of vehicle 2720. As anotherexample, navigation system 2908 may include an autonomous vehiclenavigation system configured to control the movement of vehicle 2720 asdescribed elsewhere in this disclosure. In some embodiments, navigationsystem 2908 may include an advanced driver-assistance system (ADAS)system.

FIG. 31 is a flowchart showing an exemplary process 3100 for consistentwith disclosed embodiments. Reference is also made to FIGS. 30A and 30B,which are schematic illustrations of exemplary objects in a field ofview associated with a navigation system consistent with disclosedembodiments. While process 3100 is described below using vehicle 2720 asan example, one skilled in the art would understand that server 2710 canalso be configured to perform one or more steps of process 3100.

At step 3101, processor 2901 of vehicle 2720 may determine at least oneindicator of ego motion of the host vehicle (i.e., vehicle 2720). Egomotion of the host vehicle may refer to any environmental displacementof the host vehicle with respect to a non-moving reference point orobject. An indicator of ego motion of the host vehicle may include anyinformation indicating that the host vehicle moves with respect to anon-moving reference point or object (e.g., a building, a sideline of aroad segment, an electricity pole, a light pole, a tree, etc.).

For example, vehicle 2720 may include an onboard camera configured tocapture a plurality of images from its environment. Processor 2901 maybe configured to receive the plurality of images and determine whetherthe vehicle is moving with respect to a rigid structure (i.e., anindicator of ego motion of the vehicle) based on the analysis of theplurality of images. By way of example, a camera of vehicle 2720 maycapture image 3000A illustrated in FIG. 30A and then capture image 3000Billustrated in FIG. 30B. Processor 2901 may receive and analyze images3000A and 3000B to determine that the vehicle is moving ahead withrespect to a non-moving object (e.g., object 3002, a light pole). By wayof example, processor 2901 may determine that the size of object 3002appearing in image 3000B may be greater than that in image 3000A.Processor 2901 may also determine that vehicle 2720 is moving towardobject 3002. Alternatively or additionally, the at least one indicatorof ego motion of the host vehicle may be determined based on theanalysis of map information. For example, processor 2901 may determinethe first position of vehicle 2720 on a map and determine the secondposition of vehicle 2720 on the map, and compare the first position withthe second position. Processor 2901 may also determine at least oneindicator of ego motion of the host vehicle based on the comparison(e.g., the first position being different from the second position).Alternatively or additionally, the at least one indicator of ego motionof the host vehicle may be determined based on a heading direction ofthe host vehicle. For example, vehicle 2720 may include a sensor (e.g.,a compass) configured to determine a heading direction of vehicle 2720.Processor 2901 may determine whether the heading direction changes overtime, and if so, processor 2901 may determine that the host vehicle ismoving (i.e., one indicator of ego motion of the host vehicle).Alternatively or additionally, the at least one indicator of ego motionof the host vehicle may be determined based on an analysis of an outputfrom one or more of a speedometer (e.g., indicating that the mileage ofthe host vehicle changes over time), an accelerometer (e.g., detectingan acceleration of the host vehicle), and a GPS device (e.g., detectingthe position of the host vehicle changes based on GPS signals receivedover time). Alternatively or additionally, the at least one indicator ofego motion of the host vehicle may be determined based on a series ofpoint clouds collected over time. For example, LIDAR system 2907 maygenerate a first point cloud collected at a first time point, which mayinclude a first point cloud representation of a non-moving project(e.g., a light pole). LIDAR system 2907 may generate a second pointcloud collected at a second time point after the first time point, whichmay also include a second point cloud representation of the samenon-moving project. Processor 2901 may determine at least at least oneindicator of ego motion of the host vehicle based on the difference inthe first point cloud representation and the second point cloudrepresentation (e.g., indicating the host vehicle moved toward the lightpole from the first time point to the second time point). Alternativelyor additionally, the at least one indicator of ego motion of the hostvehicle may be determined based on a combination of point clouds andimages. For example, processor 2901 may obtain a first point cloud and afirst image captured at a first time point, and a second point cloud anda second image captured at a second time. Processor 2901 may alsodetermine at least one indicator of ego motion of the host vehicle basedon the difference between the first and second point clouds, and thedifference between the first and second images.

At step 3102, processor 2901 may receive, from a LIDAR system associatedwith the host vehicle (e.g., LIDAR system 2907) and based on a firstLIDAR scan of a field of view of the LIDAR system, a first point cloud.The first point cloud may include a first representation of at least aportion of an object within the field of view of the LIDAR system. Insome embodiments, the first point cloud may be collected at a first timepoint.

As elsewhere in this disclosure, LIDAR system 2907 may include a lasersource configured to emit a laser (e.g., a continuous laser or pulsedlaser emissions) into the field of view of LIDAR system 2907. LIDARsystem 2907 may include one or more sensors configured to detect thereflections of the laser from one or more objects in the field of view.LIDAR system 2907 may generate a point cloud (e.g., a 3D point cloud)that includes light intensity and depth/distance information relative toeach collected point by the sensor(s).

LIDAR system 2907 may generate a first point cloud includingthree-dimensional coordinates for a plurality of locations in the fieldof view of LIDAR system 2907 at which a plurality of laser reflectionsare detected by LIDAR system 2907 at the first time point. LIDAR system2907 may also transmit the generated first point cloud to processor 2901for further processing. The first point cloud may include a firstrepresentation of at least a portion of an object within the field ofview of LIDAR system 2907. A representation of at least a portion of anobject included in a point cloud refers to a collection of informationrelating to laser reflections by the at least a portion of the objectdetected by one or more sensors of LIDAR system 2907.

In some embodiments, LIDAR system 2907 may also output to processor 2901various types of depth maps representative of light reflection amplitudeand distance to points within the field of view.

At step 3103, processor 2901 may receive, from LIDAR system 2907 andbased on a second LIDAR scan of the field of view of LIDAR system 2907,a second point cloud including a second representation of the at least aportion of the object. The second point cloud may include a secondrepresentation of at least a portion of an object within the field ofview of LIDAR system 2907. In some embodiments, the second point cloudmay be collected at a second time point. The second time point may occurafter the first time point.

In some embodiments, the second point cloud may includethree-dimensional coordinates for a plurality of locations in the fieldof view of LIDAR system 2907 at which a plurality of laser reflectionsare detected by LIDAR system 2907.

At step 3104, processor 2901 may determine a velocity of the objectbased on the at least one indicator of ego motion of the host vehicle,and based on a comparison of the first point cloud (which may includethe first representation of the at least a portion of the object) andthe second point cloud (which may include the second representation ofthe at least a portion of the object). In some embodiments, determiningthe velocity of the host vehicle may include determining a speed of theobject and/or a direction of the object.

In some embodiments, processor 2901 may determine the velocity of theobject based on at least one actual point cloud difference between thefirst and second point clouds. An actual point cloud difference betweentwo point clouds refers to the differences in the data of the two pointclouds. As described elsewhere in this disclosure, a point cloud is acollection of light intensity and depth/distance information relative toeach collected point by the sensor(s) of LIDAR system 2907. Processor2901 may subtract the data of the first point cloud from the data thesecond point cloud to determine an actual point cloud difference.

In some embodiments, processor 2901 may also determine an expected pointcloud difference between the first and second point clouds due to theego motion of the host vehicle. As explained above, when the hostvehicle moves, an object may move in the field of view of LIDAR system2907. For example, the location of a non-moving object in the field ofview of LIDAR system 2907 may change if the host vehicle moves.Processor 2901 may determine an expected point cloud difference betweenthe first point cloud and the second point cloud based on the velocityand/or direction of the host vehicle (which may be determined asdescribed elsewhere in this disclosure). An expected point clouddifference refers to the differences between the first point cloud,which may be a measured data set measured at the first time point) andan expected point cloud at the second time point, which may becalculated based on the first point cloud and the determined ego motionof the host vehicle (e.g., the velocity and/or direction of the hostvehicle). For example, processor 2901 may determine an expected pointcloud difference based on a change of a location of object 3002 (or atleast a portion thereof) relative to a field of view of LIDAR system2907 from the first time point to the second time point, based on thevelocity and direction of the host vehicle and the first point cloud. Byway of example, the location of object 3002 (illustrated in image 3000Aand image 3000B) may be expected to shift toward upper and right in thefield of view of LIDAR system 2907 when the host vehicle is movingstraight. Processor 2901 may determine an expected point clouddifference relating to the change of the location of object 3002 basedon the velocity and/or direction of the host vehicle and the location ofobject 3001 in the first point cloud. Alternatively or additionally,processor 2901 may determine an expected change of the size of object3002 (or at least a portion thereof) appearing in an expected secondpoint cloud at the second time point (which may be a calculated data setcompared to the measured second point cloud) relative to the first pointcloud representation of object 3002 in the first point cloud. Forexample, the size of object 3002 appearing in the expected second pointcloud at the second time point may increase compared to the size ofobject 3002 appearing in the first point cloud at the first time point.Processor 2901 may also determine an expected point cloud differencebased on the expected change of the size of object 3002 (or at least aportion thereof). Processor 2901 may further determine the velocity ofthe object based on a comparison of the actual and expected point clouddifferences. For example, if processor 2901 determines that there is nodifference between the actual and expected point clouds (or thedifference between the actual and expected point clouds is less than athreshold), processor 2901 may determine that the velocity of object3002 equals zero (i.e., object 3002 is not moving). As another example,as described above, processor 2901 may determine a change of the size ofthe point cloud representation of object 3001 in the expected secondpoint cloud (which may be a calculated point cloud at the second timepoint based on the first point cloud and the velocity and/or directionof the host vehicle) relative to the first point cloud representation ofobject 3001 in first point cloud based on the velocity and/or directionof the host vehicle. As another example, processor 2901 may determinethe velocity of object 3001 (a moving vehicle) based on a comparison ofthe actual and expected point cloud differences relating to object 3001,similar to the determination of the velocity of object 3002 describedabove. Processor 2901 may also determine that the actual and expectedpoint cloud differences relating to object 3001 may indicate thevelocity of object 3001 is not zero.

In some embodiments, processor 2901 may determine the velocity of thehost vehicle based on a comparison of two or images and the at least oneindicator of ego motion of the host vehicle. For example, a camera ofvehicle 2720 may capture image 3000A illustrated in FIG. 30A at thefirst time point and then capture image 3000B illustrated in FIG. 30B atthe second time point. Image 3000A may include a first imagerepresentation of at least a portion of object 3002 (and at least aportion of object 3001), and image 3000B may include a second imagerepresentation of the at least a portion of object 3002 (and at least aportion of object 3001). Processor 2901 may determine a velocity ofobject 3002 based on a comparison of image 3000A and image 3000B,(and/or the at least one indicator of ego motion of the host vehicle,and based on a comparison of the first point cloud and the second pointcloud). In some embodiments, processor 2901 may determine a velocity ofobject 3001 based on a comparison of image 3000A and image 3000B, eachof which may include image representations of object 3001, similar tothe determination of the velocity of object 3002 described above.

In some embodiments, processor 2901 may determine the velocity of anobject based on the comparison between an actual image difference and anexpected image difference. An actual image difference between two imagesrefers to the differences in the data of the two images. An imagecaptured by a camera may include pixels having light intensity (or othertypes of information) corresponding to the points in the field of viewof the camera. Processor 2901 may subtract the pixel data of the firstimage from the pixel data of the second image to determine an actualimage difference. For example, processor 2901 may determine at least oneactual image difference between image 3000A and image 3000B by, forexample, subtracting the first image from the second image.

Processor 2901 may also determine an expected image difference betweenthe first image (which is a collection of measured data at the firsttime point) and an expected second image (which may be a collection ofcalculated data at the second time point) based on the at least oneindicator of ego motion of the host vehicle (e.g., the velocity and/ordirection of the host vehicle determined as described elsewhere in thisdisclosure). For example, when the host vehicle moves, an object maymove in the field of view an onboard camera of the host vehicle.Processor 2901 may calculate a difference between image 3000A (which maybe captured at the first time point) and an expected image at the secondtime point (which may be calculated based on the ego motion of the hostvehicle) based on the at least one indicator of ego motion of the hostvehicle. For example, processor 2901 may determine an expected imagedifference based on a change of a location of object 3002 (or at least aportion thereof) relative to a field of view of the camera (e.g., theview of image 3000A) based on the velocity and direction of the hostvehicle. By way of example, as illustrated in FIGS. 30A and 30B, thelocation of object 3002 (i.e., a non-moving object at the right side ofthe field of view of the camera) is expected to shift toward upper andright in the field of view of the camera when the host vehicle is movingstraight. Processor 2901 may determine an expected image differencerelating to the change of the location of object 3002 based on thevelocity and/or direction of the host vehicle and the location of object3001 in image 3000A. Alternatively or additionally, processor 2901 maydetermine an expected image difference based on a change of the size ofthe image representation of object 3002 in an expected image at thesecond time point relative to the first image representation of object3002 in image 3000A (e.g., an expected increase in the size appearing inimage 3000B compared to the size appearing in image 3000A). Processor2901 may further determine the velocity of the object based on acomparison of the actual and expected image differences. For example, ifprocessor 2901 determines that there is no difference between the actualand expected images (or the difference between the actual and expectedimages is less than a threshold), processor 2901 may determine that thevelocity of object 3002 equals zero (i.e., object 3002 is not moving).As another example, processor 2901 may determine an expected change ofthe size of the second image representation of object 3001 in image3000B relative to the first image representation of object 3001 in image3000A based on the velocity and/or direction of the host vehicle. Asanother example, processor 2901 may determine the velocity of object3001 (a moving vehicle) based on a comparison of the actual and expectedimage differences relating to object 3001, similar to the determinationof the velocity of object 3002 described above.

In some embodiments, processor 2901 may determine the velocity of anobject based on the comparison of the actual and expected point clouddifferences and the comparison of the actual and expected imagedifferences. For example, processor 2901 may determine a firstpreliminary velocity of an object based on the actual and expected pointcloud differences (as described elsewhere in this disclosure) anddetermine a second preliminary velocity of the object and the comparisonof the actual and expected image differences (as described elsewhere inthis disclosure). Processor 2901 may also determine the velocity of theobject based on the first preliminary velocity and the secondpreliminary velocity. For example, processor 2901 may determine anaverage velocity of the first preliminary velocity and the secondpreliminary velocity) as the velocity of the object. As another example,in determining the velocity of the object, processor 2901 may assign afirst weight to a result of the comparison of the actual and expectedpoint cloud differences (e.g., the first preliminary velocity) andassign a second weight to a result of the comparison of the actual andexpected image differences (e.g., the second preliminary velocity).Processor 2901 may also determine the velocity of the object based on,for example, a weighted average based on the sum of the product of thefirst weight times the first preliminary velocity and the product of thesecond weight times second preliminary velocity. In some embodiments,the first and second weights may be different. Alternatively, the firstand second weights may be equal.

In some embodiments, processor 2901 may determine whether the object ismoving based on the velocity of the object. For example, processor 2901may determine the velocity of object 3001 illustrated in FIGS. 30A and30B is not zero (which may be determined based on one or more steps asdescribed elsewhere in this disclosure) and determine that object 3001is moving.

In some embodiments, processor 2901 may determine at least onenavigational action for the host vehicle based on the velocity of theobject. For example, processor 2901 may determine that an object ismoving towards the host vehicle based on the determined velocity (whichmay include a speed and a direction). Processor 2901 may also determineat least one navigational action for the host vehicle. For example,processor 2901 may determine a navigational action for the host vehicle,including, for example, at least one of accelerating, braking, orturning the host vehicle), to avoid a collision with the object.Processor 2901 may also instruct navigation system 2908 to implement theat least one navigational action.

In some embodiments, processor 2901 may determine whether to update (orcause an update to) a map based on the velocity of the object. Forexample, processor 2901 may determine that object 3002 is a non-movingobject based on the velocity of object 3002 and determine not to updatea map. On the other hand, assuming that processor 2901 determines thatobject 3002 is a moving object based on the velocity of object 3002,processor 2901 may update a map stored in a local storage device byremoving object 3002 from the map (if object 3002 is included in themap). Alternatively or additionally, processor 2901 may transmit theinformation of object 3002 (e.g., being a moving object) to server 2710,which may update a map based on the received information.

In some embodiments, processor 2901 may determine the location of theobject based on the velocity of the object. For example, processor 2901may determine that the velocity of object 3002 illustrated in FIGS. 30Aand 30B is zero and determine the location of object 3002. Processor2901 may also transmit the location of object 3002 to server 2710 (e.g.,GPS coordinates of object 3002 and/or a location relative to a knownobject) via, for example, network 2730. Server 2710 may be configured toupdate a map based on the received location of object 3002. For example,server 2710 may add the location of object 3002 into a map or modify thelocation of object 3002 in a map based on the received location ofobject 3002. As another example, processor 2901 may determine that thevelocity of an object is not zero (i.e., the object was moving at leastduring the period of detecting) and determine a location or locations ofthe object. Processor 2901 may also transmit the location(s) of theobject to server 2710, which may modify a map based on the receivedlocation(s) of the object. For example, a map may previously indicatethe object is a non-moving object (e.g., a road sign). Server 2710 mayreceive the location(s) of the object to server 2710 indicating that thelocation of the object changed. Server 2710 may update the map by, forexample, modifying the location of the object or removing the objectfrom the map. In some embodiments, server 2710 may receive locationinformation of an object from a plurality of vehicles 2720. Server 2710may update a map based on the location information received from theplurality of vehicles 2720. For example, server 2710 may be configuredto update a map only when a percentage of the location informationreceived from the plurality of vehicles 2720 indicating that the objectis moving is equal to or greater than a threshold.

LIDAR Sparse Map Localization

This disclosure provides systems and methods for determining a positionof a host vehicle based on LIDAR data captured by a LIDAR system onboardthe host vehicle. In one embodiment, a system may analyze LIDAR datacaptured by the LIDAR system to identify a landmark associated with aroad segment in an environment of the host vehicle. The system may alsodetermine whether the identified landmark matches a landmark in a sparsemap (which is also referred to herein as a mapped landmark) received bythe system from a server. The sparse map may be generated by the serverbased on data collected by multiple vehicles, as described elsewhere inthis disclosure. The system may further determine a position of the hostvehicle by, for example, comparing the representation of the landmark inthe LIDAR data captured by the LIDAR system with the mapped landmark inthe sparse map.

FIG. 32 illustrates an exemplary system 3200 for generating a sparse mapbased on information collected by a plurality of vehicles consistentwith disclosed embodiments. As illustrated in FIG. 32 , system 3200 mayinclude a server 3210, one or more vehicles 3220 (e.g., vehicle 3220 a,vehicle 3220 b, . . . , vehicle 3220 n), a network 3230, and a database3240.

Vehicle 3220 may collect information from its environment and transmitthe collected information to server 3210 via, for example, network 3230.In one example, vehicle 3220 may include one or more sensors (e.g., acamera, a speedometer, a GPS device, an accelerometer, etc.) configuredto collect data and information from its environment. Vehicle 3220 maytransmit the data and information (or the derived data therefrom) toserver 3210. By way of example, vehicle 3220 may include an image sensor(e.g., a camera) configured to capture one or more images of itsenvironment. Alternatively or additionally, vehicle 3220 may include aLIDAR system configured to gather LIDAR reflection information within a360-degree field of view around vehicle 3220 or from any sub-segment ofthe 360-degree field of view (e.g., one or more FOVs each representingless than 360 degrees). Alternatively or additionally, an onboard sensor(e.g., a GPS device, an imaging sensor, etc.) may record data relatingto the trajectory of vehicle 3220 along one or more road segments.Vehicle 3220 may further be configured to transmit collecteddata/information to server 3210 via network 3230.

Server 3210 may process data/information received from one or morevehicles 3220. For example, server 3210 may generate or update a map(e.g., a sparse map) based on the received data/information, asdescribed elsewhere in this disclosure. In one example, server 3210 maybe configured to receive from vehicle 3220 data relating to a landmarkassociated with a road segment (e.g., the landmark's location, type,size, shape, semantic property (if any), etc.). Server 3210 may update amap to add or modify the landmark based on the received information fromvehicle 3220. As another example, server 3210 may be configured toreceive from vehicle 3220 data relating to a trajectory of vehicle 3220along a road segment. Server 3210 may also be configured to update asparse map by updating a target trajectory associated with the roadsegment based on the received data. Server 3210 may further beconfigured to transmit map data of one or more sparse maps to one ormore vehicles (e.g., vehicle 3220, vehicle 3400, etc.).

In some embodiments, a sparse map may include one or more targettrajectories associated with one or more road segments. For example, asparse map may include one or more target trajectories, each of whichmay be represented in the sparse map by a three-dimensional splinesimilar to three-dimensional spline 950 illustrated in FIG. 9B anddescribed above.

In some embodiments, a sparse map may include information relating to alandmark associated with a road segment. For example, as describedabove, a LIDAR system onboard a host vehicle (e.g., vehicle 3220illustrated in FIG. 32 ) may capture reflection information from itsfield of view in the environment of the vehicle. The reflectioninformation may include information relating to reflections by alandmark in the field of view. Vehicle 3220 may transmit the capturedLIDAR data to server 3210, which may analyze the LIDAR data and identifythe landmark in the LIDAR data (e.g., in the form of point cloudinformation). Server 3210 may also be configured to include therepresentation of the identified landmark in the point cloud informationin a sparse map. Alternatively or additionally, server 3210 maydetermine the size, shape, and/or location of the landmark based on thepoint cloud information, and include the size, shape, and/or location ofthe landmark in the sparse map.

In some embodiments, a landmark may be represented in a sparse map by apoint location. Alternatively, a landmark may be represented in a sparsemap by multiple point locations. For example, a landmark may be aspeed-limit sign fixed to one side of a bridge over a road segmenthaving lanes in two opposite directions. The landmark may be representedin a sparse map by two point locations, each of which may be associatedwith one of the directions of the road segment. Alternatively oradditionally, a landmark may be represented in a sparse map by an objecttype classification. For example, a semantic sign (i.e., a landmark),which may include any class of signs for which there's a standardizedmeaning (e.g., speed limit signs, warning signs, directional signs,etc.), may be represented in a sparse map by an object typeclassification (e.g., a stop sign, a speed-limit sign, etc.).Alternatively or additionally, a landmark may be represented in a sparsemap by one or more object descriptors. For example, a non-semantic sign,which may include any sign that is not associated with a standardizedmeaning (e.g., general advertising signs, signs identifying businessestablishments, etc.), may be represented in a sparse map by one or moreobject descriptors (e.g., the content of the advertising sign).

In some embodiments, a sparse map may include LIDAR data and/or imagedata relating to a landmark. For example, as described above, a vehicle(e.g., vehicle 3220) may transmit LIDAR data and/or image data, whichmay include representation of a landmark in LIDAR data and/or imagedata, to server 3210. Server 3210 may analyze the data and identify alandmark in the LIDAR data (e.g., in the form of point cloudinformation) and/or image data (e.g., in the form of one or moreimages). Server 3210 may also associate relevant LIDAR and/or image datawith the identified image and include the relevant LIDAR and/or imagedata into a sparse map. For example, server 3210 may includerepresentation of a landmark in point cloud information and/or one ormore images captured from a point in a target trajectory (e.g., targettrajectory 3531 illustrated in FIG. 35B) into a sparse map (e.g., sparsemap 3500).

While FIG. 32 illustrates one server 3210, one skilled in the art wouldunderstand that system 3200 may include one or more servers 3210 that,individually or in combination, perform the functions of server 3210disclosed in this application. For example, server 3210 may constitute acloud server group comprising two or more servers that perform thefunctions disclosed herein. The term “cloud server” refers to a computerplatform that provides services via a network, such as the Internet. Inthis example configuration, server 3210 may use virtual machines thatmay not correspond to individual hardware. For example, computationaland/or storage capabilities may be implemented by allocating appropriateportions of computation/storage power from a scalable repository, suchas a data center or a distributed computing environment. In one example,server 3210 may implement the methods described herein using customizedhard-wired logic, one or more Application Specific Integrated Circuits(ASICs) or Field Programmable Gate Arrays (FPGAs), firmware, and/orprogram logic which, in combination with the computer system, causeserver 3210 to be a special-purpose machine.

Network 3230 may be configured to facilitate communications among thecomponents of system 3200. Network 3230 may include wired and wirelesscommunication networks, such as a local-area network (LAN), a wide-areanetwork (WAN), a computer network, a wireless network, atelecommunications network, or the like, or a combination thereof.

Database 3240 may be configured to store information and data for one ormore components of system 3200. For example, database 3240 may storedata (e.g., map data) for server 3210. One or more vehicles 3220 mayobtain map data stored in database 3240 via, for example, network 3230.

FIG. 33 illustrates an exemplary server 3210 consistent with disclosedembodiments. As illustrated in FIG. 28 , server 2710 may include atleast one processor (e.g., processor 2801), a memory 2802, at least onestorage device (e.g., storage device 2803), a communications port 2804,and an I/O device 2805.

Processor 3301 may be configured to perform one or more functions ofserver 3210 described in this disclosure. Processor 3301 may include amicroprocessor, preprocessors (such as an image preprocessor), agraphics processing unit (GPU), a central processing unit (CPU), supportcircuits, digital signal processors, integrated circuits, memory, or anyother types of devices suitable for running applications or performing acomputing task. In some embodiments, processor 3301 may include any typeof single or multi-core processor, mobile device microcontroller,central processing unit, etc. Various processing devices may be used,including, for example, processors available from manufacturers such asIntel®, AMD®, etc., or GPUs available from manufacturers such asNVIDIA®, ATI®, etc. and may include various architectures (e.g., x86processor, ARM®, etc.). Any of the processing devices disclosed hereinmay be configured to perform certain functions. Configuring a processingdevice, such as any of the described processors or other controller ormicroprocessor, to perform certain functions may include programming ofcomputer-executable instructions and making those instructions availableto the processing device for execution during operation of theprocessing device. In some embodiments, configuring a processing devicemay include programming the processing device directly witharchitectural instructions. For example, processing devices such asfield-programmable gate arrays (FPGAs), application-specific integratedcircuits (ASICs), and the like may be configured using, for example, oneor more hardware description languages (HDLs).

Server 3210 may also include a memory 3302 that may store instructionsfor various components of server 3210. For example, memory 3302 maystore instructions that, when executed by processor 3301, may beconfigured to cause processor 3301 to perform one or more functionsdescribed herein. Memory 3302 may include any number of random-accessmemories, read-only memories, flash memories, disk drives, opticalstorage, tape storage, removable storage, and other types of storage. Inone instance, memory 3302 may be separate from processor 3301. Inanother instance, memory 3302 may be integrated into processor 3301.

Storage device 3303 may be configured to store various data andinformation for one or more components of server 3210. For example,storage device 3303 may store map data. Server 3210 may update the mapdata based on the data and/or information received from one or morevehicles 3220. Server 3210 may also store the updated map data intostorage device 3303. Storage device 3303 may include one or more harddrives, tapes, one or more solid-state drives, any device suitable forwriting and read data, or the like, or a combination thereof.

Communications port 3304 may be configured to facilitate datacommunications between server 3210 and one or more components of system3200 via network 3230. For example, communications port 3304 may beconfigured to receive data from and transmit data to one or morecomponents of system 100 via one or more public or private networks,including the Internet, an Intranet, a WAN (Wide-Area Network), a MAN(Metropolitan-Area Network), a wireless network compliant with the IEEE802.11a/b/g/n Standards, a leased line, or the like.

I/O device 3305 may be configured to receive input from the user ofserver 3210, and one or more components of server 3210 may perform oneor more functions in response to the input received. In someembodiments, I/O device 3305 may include an interface displayed on atouchscreen. I/O device 3305 may also be configured to outputinformation and/or data to the user. For example, I/O device 3305 mayinclude a display configured to display map data.

FIG. 34 illustrates an exemplary vehicle 3400 consistent with disclosedembodiments. As illustrated in FIG. 34 , vehicle 3400 may include atleast one processor (e.g., processor 3401), a memory 3402, at least onestorage device (e.g., storage device 3403), a communications port 3404,an I/O device 3405, one or more sensors 3406, a LIDAR system 3407, and anavigation system 3408. In some embodiments, one or more vehicles 3220may be implemented using one or more components of vehicle 3400.

Processor 3401 may be programmed to perform one or more functions ofvehicle 3400 described in this disclosure. Processor 3401 may include amicroprocessor, preprocessors (such as an image preprocessor), agraphics processing unit (GPU), a central processing unit (CPU), supportcircuits, digital signal processors, integrated circuits, memory, or anyother types of devices suitable for running applications or performing acomputing task. In some embodiments, processor 3401 may include any typeof single or multi-core processor, mobile device microcontroller,central processing unit, etc. Various processing devices may be used,including, for example, processors available from manufacturers such asIntel®, AMD®, etc., or GPUs available from manufacturers such asNVIDIA®, ATI®, etc. and may include various architectures (e.g., x86processor, ARM®, etc.). Any of the processing devices disclosed hereinmay be configured to perform certain functions. Configuring a processingdevice, such as any of the described processors or other controller ormicroprocessor, to perform certain functions may include programming ofcomputer-executable instructions and making those instructions availableto the processing device for execution during operation of theprocessing device. In some embodiments, configuring a processing devicemay include programming the processing device directly witharchitectural instructions. For example, processing devices such asfield-programmable gate arrays (FPGAs), application-specific integratedcircuits (ASICs), and the like may be configured using, for example, oneor more hardware description languages (HDLs).

Vehicle 3400 may also include a memory 3402 that may store instructionsfor various components of vehicle 3400. For example, memory 3402 maystore instructions that, when executed by processor 3401, may beconfigured to cause processor 3401 to perform one or more functions ofprocessor 3401 described herein. Memory 3402 may include any number ofrandom-access memories, read-only memories, flash memories, disk drives,optical storage, tape storage, removable storage, and other types ofstorage. In one instance, memory 3402 may be separate from processor3401. In another instance, memory 3402 may be integrated into processor3401. In some embodiments, memory 3402 may include software forperforming one or more computing tasks, as well as a trained system,such as a neural network, or a deep neural network.

Storage device 3403 may be configured to store various data andinformation for one or more components of vehicle 3400. Storage device3403 may include one or more hard drives, tapes, one or more solid-statedrives, any device suitable for writing and read data, or the like, or acombination thereof. For example, storage device 3403 may be configuredto store data of one or more maps. By way of example, storage device3403 may store data of a sparse map, which may include one or morelandmarks associated with a road segment and one or more targettrajectories associated with the road segment.

Communications port 3404 may be configured to facilitate datacommunications between vehicle 3400 and one or more components of system3200 via network 3230. For example, communications port 3404 may beconfigured to receive data from and transmit data to server 3210 via oneor more public or private networks, including the Internet, an Intranet,a WAN (Wide-Area Network), a MAN (Metropolitan-Area Network), a wirelessnetwork compliant with the IEEE 802.11a/b/g/n Standards, a leased line,or the like.

I/O device 3405 may be configured to receive input from the user ofserver 3210, and one or more components of server 3210 may perform oneor more functions in response to the input received. In someembodiments, I/O device 3405 may include an interface displayed on atouchscreen. I/O device 3405 may also be configured to outputinformation and/or data to the user. For example, I/O device 3405 mayinclude a display configured to display a map. In some embodiments,vehicle 3400 may receive data of the map (or at least a portion thereof)from server 3210 via, for example, network 3230.

Sensor 3406 may be configured to collect information relating to vehicle3400 and/or the environment of vehicle 3400. Sensor 3406 may include oneor more of an image sensor (e.g., a camera), a positioning device (e.g.,a Global Positioning System (GPS) device), an accelerometer, a gyrosensor, a speedometer, or the like, or a combination thereof. Forexample, vehicle 3400 may include an image sensor (e.g., a camera)configured to capture one or more images of its environment, which mayinclude a representation of a landmark (or at least a portion thereof).As another example, vehicle 3400 may include a GPS device configured tocollect positioning data associated with positions of vehicle 3400 overa period of time.

LIDAR system 3407 may include one or more LIDAR units. In someembodiments, the one or more LIDAR units may be positioned on a roof ofvehicle 3400. Such a unit may include a rotating unit configured togather LIDAR reflection information within a 360-degree field of viewaround vehicle 3400 or from any sub-segment of the 360-degree field ofview (e.g., one or more FOVs each representing less than 360 degrees).In some embodiments, a LIDAR unit may be positioned at a forwardlocation on vehicle 3400 (e.g., near the headlights, in the front grill,near the fog lamps, in a forward bumper, or at any other suitablelocation). In some cases, one or more LIDAR units installed on a forwardportion of vehicle 3400 may collect reflection information from a fieldof view in an environment forward of vehicle 3400. The data collected byLIDAR system 3407 may be provided to processor 3401. Alternatively oradditionally, the data may be transmitted to server 3210 and/or database3240 via network 3230.

Any suitable type of LIDAR unit may be included on vehicle 3400. In somecases, LIDAR system 3407 may include one or more flash LIDAR units(e.g., 3D flash LIDAR) where an entire LIDAR field of view (FOV) isilluminated with a single laser pulse, and a sensor including rows andcolumns of pixels to record returned light intensity and time offlight/depth information. Such flash systems may illuminate a scene andcollect LIDAR “images” multiple times per second. Scanning LIDAR unitsmay also be employed. Such scanning LIDAR units may rely on one or moretechniques for dispersing a laser beam over a particular FOV. In somecases, a scanning LIDAR unit may include a scanning mirror that deflectsand directs a laser beam toward objects within the FOV Scanning mirrorsmay rotate through a full 360 degrees or may rotate along a single axisor multiple axes over less than 360 degrees to direct the laser toward apredetermined FOV. In some cases, LIDAR units may scan one horizontalline. In other cases, a LIDAR unit may scan multiple horizontal lineswithin an FOV, effectively rastering a particular FOV multiple times persecond.

The LIDAR units in LIDAR system 3407 may include any suitable lasersource. In some embodiments, the LIDAR units may employ a continuouslaser. In other cases, the LIDAR units may use pulsed laser emissions.Additionally, any suitable laser wavelength may be employed. In somecases, a wavelength of between about 600 nm to about 1000 nm may beused.

The LIDAR unit(s) in LIDAR system 3407 may also include any suitabletype of sensor and provide any suitable type of output. In some cases,sensors of the LIDAR units may include solid state photodetectors, suchas one or more photodiodes or photomultipliers. The sensors may alsoinclude one or more CMOS or CCD devices including any number of pixels.These sensors may be sensitive to laser light reflected from a scenewithin the LIDAR FOV. The sensors may enable various types of outputfrom a LIDAR unit. In some cases, a LIDAR unit may output raw lightintensity values and time of flight information representative of thereflected laser light collected at each sensor or at each pixel orsub-component of a particular sensor. Additionally or alternatively, aLIDAR unit may output a point cloud (e.g., a 3D point cloud) that mayinclude light intensity and depth/distance information relative to eachcollected point). LIDAR units may also output various types of depthmaps representative of light reflection amplitude and distance to pointswithin a field of view. LIDAR units may provide depth or distanceinformation relative to particular points within an FOV by noting a timeat which light from the LIDAR's light source was initially projectedtoward the FOV and recording a time at which the incident laser light isreceived by a sensor in the LIDAR unit. The time difference mayrepresent a time of flight, which may be directly related to the roundtrip distance that the incident laser light traveled from the lasersource to a reflecting object and back to the LIDAR unit. Monitoring thetime of flight information associated with individual laser spots orsmall segments of a LIDAR FOV may provide accurate distance informationfor a plurality of points within the FOV (e.g., mapping to even verysmall features of objects within the FOV). In some cases, LIDAR unitsmay output more complex information, such as classification informationthat correlates one or more laser reflections with a type of object fromwhich the laser reflection was acquired.

Navigation system 3408 may be configured to assist a driver of vehicle3400 to operate vehicle 3400. For example, navigation system 3408 maydetermine that vehicle 3400 is currently deviating from a targettrajectory and generate a notification to the driver indicating thedeviation from the target trajectory, which may be displayed on adisplay (e.g., displaying the target trajectory and an estimated travelpath determined based on vehicle 3400's current position and headingdirection). Alternatively, navigation system 3408 may include anautonomous vehicle navigation system configured to control the movementof vehicle 3400, as described elsewhere in this disclosure. For example,navigation system 3408 may implement a navigation action determined byprocessor 3401 as vehicle 3400 traverses a road segment (e.g., one ormore of steering, braking, or acceleration of the vehicle). In someembodiments, navigation system 3408 may include an advanceddriver-assistance system (ADAS) system. In some embodiments, navigationsystem 3408 may access a sparse map stored in the storage device orcomputer-readable medium provided onboard vehicle 3400 in order togenerate navigational instructions for guiding vehicle 3400 as thevehicle traverses a road segment.

FIG. 35A illustrates an exemplary road segment consistent with disclosedembodiments. As illustrated in FIG. 35A, vehicle 3400 drives in lane3511, moving toward and merging into lane 3512. Lane 3512 and lane 3513are separated by a lane divider 3514, and vehicles in lane 3512 andvehicles in lane 3513 may move in opposite directions. A landmark 3521may locate near the intersection of lane 3511 and lane 3512, and alandmark 3522 may locate along lane 3512. By way of example, landmark3521 may be a stop sign, and landmark 3522 may be a speed-limit sign.

Vehicle 3400 may receive a sparse map 3500 illustrated in FIG. 35B from,for example, server 3210 consistent with disclosed embodiments. Sparsemap 3500 may include a mapped navigational landmark 3571 and a mappednavigational landmark 3572, which may respectively correspond tolandmark 3521 and landmark 3522 illustrated in FIG. 35A. Sparse map 3500may also include a target trajectory 3531 for a vehicle merging fromlane 3511 into lane 3512, a target trajectory 3532 for a vehicle movingin lane 3512, and a target trajectory 3532 for a vehicle moving in lane3513. In some embodiments, sparse map 3500 may be similar to othersparse maps provided in this disclosure (e.g., sparse map 800 describedabove) and may be generated based on various methods as describedelsewhere in this disclosure (e.g., the method for generating sparse map800 described above).

FIG. 35C illustrates vehicle 3400 merging into lane 3512 consistent withdisclosed embodiments. Vehicle 3400 may be configured to receive pointcloud information from LIDAR system 3407 (which may be onboard vehicle3400). The point cloud information may be representative of distances tovarious objects in the environment of vehicle 3400. For example, thepoint cloud information may include information reprehensive of adistance 3551 to landmark 3521 and a distance 3552 to landmark 3522.Vehicle 3400 may be configured to compare the received point cloudinformation with at least one of the mapped navigational landmarks insparse map 3500 to provide a LIDAR-based localization of vehicle 3400relative to target trajectory 3531. For example, vehicle 3400 maydetermine a current position of vehicle 3400 relative to targettrajectory 3531 based on distance 3551 and distance 3552 (which may bedetermined based on the received point cloud information). Vehicle 3400may also be configured to determine at least one navigational action forvehicle 3400 based on the LIDAR-based localization relative to targettrajectory 3531. For example, as described above, vehicle 3400 may beconfigured to determine its current position shown in FIG. 35C (alongactual trajectory 3541) in relative to target trajectory 3531 anddetermine that it deviates from target trajectory 3531 (e.g., on theright side of target trajectory 3531). Vehicle 3400 may also determineat least one navigational action, including, for example, steering inthe left direction to the extent that vehicle 3400 may follow targettrajectory 3531 (and target trajectory 3532 once it has merged into lane3512). Vehicle 3400 may further cause navigation system 3408 toimplement the determined navigation action, including, for example,steering in the left direction.

FIG. 36 is a flowchart showing an exemplary process 3600 for determininga navigational action for a host vehicle consistent with disclosedembodiments. At step 3601, processor 3401 may be programmed to receive,from an entity remotely located relative to vehicle 3400, a sparse mapassociated with at least one road segment to be traversed by vehicle3400. For example, processor 3401 may receive sparse map 3500 fromserver 3210 via network 3230. As illustrated in FIG. 35B, sparse map3500 may include mapped navigational landmark 3571 and mappednavigational landmark 3572. Sparse map 3500 may also include a targettrajectory 3531 for a vehicle merging from lane 3511 into lane 3512, atarget trajectory 3532 for a vehicle moving in lane 3512, and a targettrajectory 3532 for a vehicle moving in lane 3513. In some embodiments,sparse map 3500 (including mapped navigational landmarks 3571 and mappednavigational landmark 3572, and target trajectories 3531, 3532, and3532) may be generated by server 3210 based on drive informationcollected from a plurality of vehicles that traveled previously alongthe at least one road segment, as described elsewhere in this disclosure(e.g., in connection with the descriptions of sparse map 800 providedabove).

At step 3602, processor 3401 may be programmed to receive point cloudinformation from LIDAR system 3407 onboard vehicle 3400. In someembodiments, the point cloud information may include informationrepresentative of distances to various objects in the environment ofvehicle 3400. As elsewhere in this disclosure, LIDAR system 3407 mayinclude a laser source configured to emit a laser (e.g., a continuouslaser or pulsed laser emissions) into the field of view of LIDAR system3407. LIDAR system 3407 may include one or more sensors configured todetect the reflections of the laser from one or more objects in thefield of view. LIDAR system 2907 may generate a point cloud (e.g., a 3Dpoint cloud) that includes light intensity and depth/distanceinformation relative to each collected point by the sensor(s). By way ofexample, processor 3401 may be programmed to receive point cloudinformation representative of distance 3551 to landmark 3521 anddistance 3552 to landmark 3522 illustrated in FIG. 35C.

In some embodiments, the point cloud information received by processor3401 at step 3602 may include depth (or distance) information relatingto certain types of objects to preserve processing bandwidth. Forexample, the point cloud information may include point cloud informationassociated with one or more vertically oriented objects in theenvironment of vehicle 3400. Vertically oriented objects may be lesslikely to move compared to horizontally oriented objects such asvehicles. By way of example, the point cloud information may include atleast one of a sign post, a lamp post, a road divider stanchion, a guardrail support, and a tree trunk.

At step 3603, processor 3401 may be programmed to compare the receivedpoint cloud information with at least one of the plurality of mappednavigational landmarks in the sparse map to provide a LIDAR-basedlocalization of vehicle 3400 relative to the at least one targettrajectory. The LIDAR-based localization of vehicle 3400 refers todetermining a position of vehicle 3400 based on data captured by LIDARsystem 3407 (and in some embodiments in combination with other types ofdata). For example, LIDAR system 3407 may collect reflection informationfrom its field of view in the environment of vehicle 3400 and transmitthe collected LIDAR data to processor 3401 for further processing.Processor 3401 may be programmed to determine a distance of vehicle 3400to a landmark (e.g., landmark 3521 illustrated in FIG. 35C) based on theLIDAR data. Processor 3401 may also be programmed to identifyrepresentations in the point cloud information of a mapped navigationallandmark in a sparse map (e.g., mapped navigational landmark 3571illustrated in FIG. 35B) and determine the position of vehicle 3400 inrelative to a target trajectory (e.g., target trajectory 3531illustrated in FIG. 35C) based on the determined distance of vehicle3400 to landmark 3521 (e.g., distance 3551 illustrated in FIG. 35C).

In some embodiments, processor 3401 may be programmed to provide aLIDAR-based localization of vehicle 3400 relative to a target trajectorybased on one or more aspects of a mapped navigational landmarkrepresented in the point cloud information. For example, processor 3401may be programmed to identify a representation in the point cloudinformation of a mapped navigational landmark (e.g., mapped navigationallandmark 3571 illustrated in FIG. 35B). Processor 3401 may also beprogrammed to determine one or more aspects of the mapped navigationallandmark. For example, processor 3401 may determine at least one of asize or a two-dimensional location within a LIDAR scan frame of therepresentation of the mapped navigational landmark in the point cloudinformation captured by LIDAR system 3407. Processor 3401 may also beprogrammed to an expected set of characteristics for the mappednavigational landmark determined based on the sparse map (which mayinclude the size, the location, and/or the shape of the landmark). Anexpected characteristic of a mapped navigational landmark refers to acharacteristic of the mapped navigational landmark that would berepresented in point cloud information viewed from a point on a targettrajectory. For example, processor 3401 may determine a point on targettrajectory 3531 (illustrated in FIG. 35C) that may potentiallycorrespond to the current position of vehicle 3400 and determine anexpected set of characteristics for mapped navigational landmark 3571(e.g., including, for example, the size and the two-dimensional locationthereof) viewed from that point on target trajectory 3531. By way ofexample, as described above, processor 3401 may determine a distance ofvehicle 3400 to landmark 3521 based on the point cloud informationcaptured by LIDAR system 3407. Processor 3401 may also determine a pointon target trajectory 3531 having the same distance from mappednavigational landmark 3571 in sparse map 3500. Processor 3401 mayfurther determine an expected set of characteristics for mappednavigational landmark 3571 (including, for example, the size and/or thetwo-dimensional location of landmark 3521) viewed from that point ontarget trajectory 3531. Processor 3401 may compare one or more aspectsof the mapped navigational landmark represented in the point cloudinformation (e.g., a size of mapped navigational landmark 3571 appearingin the point cloud information) to an expected set of characteristicsfor the mapped navigational landmark determined based on the sparse map(e.g., an expected size of mapped navigational landmark 3571). Processor3401 may also determine a current position of vehicle 3400 relative to atarget trajectory (e.g., target trajectory 3531 illustrated in FIG. 35C)based on the comparison. For example, if the difference between the sizeof mapped navigational landmark 3571 appearing in the point cloudinformation and the expected size of mapped navigational landmark 3571is less than a threshold, processor 3401 may determine that the currentposition of vehicle 3400 falls on target trajectory 3531. On the otherhand, if the difference is greater than a threshold, processor 3401 maydetermine the current position of vehicle 3400 is off from targettrajectory 3531. By way of example, if the size of mapped navigationallandmark 3571 appearing in the point cloud information is smaller thanthe expected size of mapped navigational landmark 3571, processor 3401may determine that the current position of vehicle 3400 is on the rightside of target trajectory 3531 (as illustrated in FIG. 35C) becausevehicle 3400 is further away from landmark 3521 than from an expectedposition in target trajectory 3531.

In some embodiments, processor 3401 may be programmed to provide aLIDAR-based localization of vehicle 3400 relative to a target trajectorybased on two or more landmarks detected from the environment of vehicle3400. For example, processor 3401 may be programmed to identifyrepresentations in the point cloud information of two mappednavigational landmarks. Processor 3401 may also be programmed todetermining, based on the point cloud information, relative distancesbetween a reference point associated with vehicle 3400 and each ofmapped navigational landmark 3571 and mapped navigational landmark 3522.In some embodiments, the reference point may be located on LIDAR system3407 onboard vehicle 3400 (e.g., LIDAR system 3407 may be installed onthe top of vehicle 3400). Processor 3401 may further be programmed todetermine the current position of vehicle 3400 relative to a targettrajectory (e.g., target trajectory 3531 illustrated in FIG. 35C) basedon the relative distances between the reference point associated withvehicle 3400 and each of the mapped navigational landmarks (e.g.,distance 3551 to mapped navigational landmark 3571 and distance 3552 tomapped navigational landmarks 3572).

In some embodiments, processor 3401 may identify representations in thepoint cloud information of two mapped navigational landmarks using atrained neural network. The trained neural network may be obtained fromserver 3210 via network 3230 or a local storage. The trained neuralnetwork may be trained using a plurality of training samples.

In some embodiments, processor 3401 may be programmed to provide aLIDAR-based localization of vehicle 3400 relative to a target trajectorybased on two or more LIDAR scans. For example, LIDAR system 3407 maycapture LIDAR data in a first LIDAR scan during a first time period (andreferred herein as the first LIDAR scan point cloud) and capture LIDARdata in a second LIDAR scan during a second time period (and referredherein as the second LIDAR scan point cloud). Processor 3401 may beprogrammed to identify a representation in the first LIDAR scan pointcloud of a mapped navigational landmark, and determine, based on thefirst LIDAR scan point cloud, a first relative distance between areference point associated with vehicle 3400 (e.g., from LIDAR system3407) and the mapped navigational landmark. Processor 3401 may also beprogrammed to identify a representation in the second LIDAR scan pointcloud of the mapped navigational landmark, and determine, based on thesecond scan point cloud, a second relative distance between thereference point associated with vehicle 3400 and the mapped navigationallandmark. Processor 3401 may further determine a current position ofvehicle 3400 relative to a target trajectory based on the first andsecond relative distances. For example, processor 3401 may determine theposition of vehicle 3400 relative to a target trajectory based on thetwo relative distances obtained at the two LIDAR scans according totriangulation (i.e., determining the location of a point by formingtriangles to vehicle 3400 from known points).

In some embodiments, in determining a LIDAR-based localization ofvehicle 3400 relative to a target trajectory based on two or more LIDARscans, processor 3401 may be programmed to take in account ego motion ofvehicle 3400 between a first time associated with acquisition of thefirst LIDAR scan point cloud and a second time associated withacquisition of the second LIDAR scan point cloud. As described elsewherein this disclosure, the ego motion of the host vehicle may refer to anyenvironmental displacement of the host vehicle with respect to anon-moving reference point or object. For example, as describedelsewhere in this disclosure, the ego motion of the vehicle body may beestimated based on an optical flow analysis of captured images by acamera onboard vehicle 3400 (or other methods described in thisdisclosure). Processor 3401 may be programmed to subtract the ego motionbetween the first time and the second time when determining a positionof vehicle 3400.

In some embodiments, processor 3401 may be programmed to provide animage-based localization of vehicle 3400 relative to a target trajectorybased on image data. For example, processor 3401 may be programmed toreceive, from a camera onboard vehicle 3400, at least one captured imageincluding a representation of at least a portion of an environment ofvehicle 3400. Processor 3401 may also be programmed to identifyrepresentations in the at least one captured image of one or more mappednavigational landmarks (e.g., an image including landmark 3522).Processor 3401 may further be programmed to determine a position ofvehicle 3400 relative to a target trajectory (e.g., target trajectory3531) based on sparse map 3500 and based on the representations in theat least one captured image (which may include landmark 3522) to providean image-based localization. For example, as described elsewhere in thisdisclosure, a sparse map may include image representation of a landmark(e.g., landmark 3522) captured from a point in target trajectory 3531.Processor 3401 may compare the image representation of landmark 3522 insparse map 3500 with the image representation of landmark 3522 in thecaptured image by the camera onboard vehicle 3400 to determine aposition of vehicle 3400 relative to target trajectory 3531. By way ofexample, if the image representation of landmark 3522 in the capturedimage by the camera onboard vehicle 3400 appears bigger than the imagerepresentation of landmark 3522 in sparse map 3500, processor 3401 maydetermine that vehicle 3400 is on the right side of target trajectory3531 (as illustrated in FIG. 35C).

In some embodiments, processor 3401 may be programmed to determine aposition of vehicle 3400 based on a LIDAR-based localization and animage-based localization. For example, processor 3401 may be programmedto a LIDAR-based localization based on LIDAR data and determine animage-based localization based on image data as described elsewhere inthis disclosure. Processor 3401 may also be programmed to determine aposition of vehicle 3400 based on the position obtained from theLIDAR-based localization and the position obtained from the image-basedlocalization by, for example, determining an average position betweenthe two positions. In some embodiments, processor 3401 may be programmedto apply weights to the each of the LIDAR-based localization and theimage-based localization to determine two weighted positions. Processor3401 may also be programmed to determine a position of vehicle 3400based on the weighted positions. The weight applied to a LIDAR-basedlocalization and the weight applied to an image-based localization maybe the same or different. In some embodiments, the weight applied to aLIDAR-based localization and/or the weight applied to an image-basedlocalization may be adjusted based on one or more current environmentconditions of vehicle 3400. For example, if vehicle 3400 is in a foggyenvironment, which may affect detection of objects using LIDAR data, theweight applied to a LIDAR-based localization may be decreased byprocessor 3401. As another example, if it is at night, which may affectdetection of objects using image data, the weight applied to animage-based localization may be decreased by processor 3401.

In some embodiments, processor 3401 may also determine a differenceassociated with the LIDAR-based localization and the image-basedlocalization (e.g., a difference between the position of vehicle 3400determined based on LIDAR data and the position of vehicle 3400determined based on image data). Processor 3401 may further determinewhether the difference between the two positions exceeds a predeterminedthreshold. A position difference exceeding the predetermined thresholdmay indicate a potential issue with LIDAR system 3407 and/or the camera.Processor 3401 may implement at least one remedial action if thedifference exceeds a predetermined threshold. For example, processor3401 may implement at least one of slowing vehicle 3400, stoppingvehicle 3400, and issuing a warning of a system irregularity. In someembodiments, processor 3401 may be programmed to determine a reason forthe difference. For example, processor 3401 may receive informationrelating to the weather condition (e.g., via a weather sensor onboardvehicle 3400 and/or from server 3210) and determine that it is snowing.Processor 3401 may determine that a difference between the position ofvehicle 3400 determined based on LIDAR data and the position determinedbased on image data may be caused by the snow. In some embodiments,processor 3401 may also provide the determined reason to the driver(and/or a passenger) with an alert displayed on a display onboard or viaa speaker of vehicle 3400.

At step 3604, processor 3401 may be programmed to determine at least onenavigational action for vehicle 3400 based on the LIDAR-basedlocalization of vehicle 3400 relative to the at least one targettrajectory. In one example, if processor 3401 determines that vehicle3400 is expected to follow target trajectory 3531 (illustrated in FIG.35B) based on the LIDAR-based localization of vehicle 3400 relative totarget trajectory 3531 and determine a navigational action ofmaintaining a current heading direction for vehicle 3400 such thatvehicle 3400 may continue to follow target trajectory 3531. On the otherhand, if processor 3401 determines that vehicle 3400 is off from targettrajectory 3531 (as illustrated in FIG. 35C), processor 3401 may beprogrammed to determine a navigational action of changing a currentheading direction for vehicle 3400 to reduce a distance between vehicle3400 and target trajectory 3531. For example, processor 3401 may beprogrammed to determine a navigational action of steering vehicle 3400to the left direction such that the distance between vehicle 3400 andtarget trajectory 3531 may be reduced.

Referring FIG. 36 , at step 3605, processor 3401 may be programmed tocause the at least one navigational action to be taken by vehicle 3400.For example, processor 3401 may cause navigation system 3408 toimplement the determined navigational action (e.g., steering vehicle3400 to the left direction).

LIDAR-Camera Fusion Based on Ego Motion

This disclosure provides systems and methods for correlating LIDAR depthinformation captured by a LIDAR system onboard a host vehicle with animage by an onboard camera to provide depth information for each ofpixels of the image (or a portion thereof). Since there may be 6 degreesof freedom between the camera and LIDAR system, the movement of the hostvehicle may need to be taken into account for correlating LIDAR depthinformation with an image. This disclosure provides a solution todetermine the host vehicle's ego motion and to use the determined egomotion over time to correlate captured LIDAR depth information withcaptured images. Based on the per-pixel depth information added into theimage, the system may cause one or more navigational responses in thehost vehicle, such as maintaining or changing a current headingdirection.

FIG. 37 illustrates an exemplary vehicle 3700 consistent with disclosedembodiments. The disclosed systems and methods may be implemented usingone or more components of vehicle 3700. As illustrated in FIG. 37 ,vehicle 3700 may include at least one processor (e.g., processor 3701),a memory 3702, at least one storage device (e.g., storage device 3703),a communications port 3704, an I/O device 3705, a camera 3706, a LIDARsystem 3707, and a navigation system 3708.

Processor 3701 may be programmed to perform one or more functions ofvehicle 3700 described in this disclosure. Processor 3701 may include amicroprocessor, preprocessors (such as an image preprocessor), agraphics processing unit (GPU), a central processing unit (CPU), supportcircuits, digital signal processors, integrated circuits, memory, or anyother types of devices suitable for running applications or performing acomputing task. In some embodiments, processor 3701 may include any typeof single or multi-core processor, mobile device microcontroller,central processing unit, etc. Various processing devices may be used,including, for example, processors available from manufacturers such asIntel®, AMD®, etc., or GPUs available from manufacturers such asNVIDIA®, ATI®, etc. and may include various architectures (e.g., x86processor, ARM®, etc.). Any of the processing devices disclosed hereinmay be configured to perform certain functions. Configuring a processingdevice, such as any of the described processors or other controller ormicroprocessor, to perform certain functions may include programming ofcomputer-executable instructions and making those instructions availableto the processing device for execution during operation of theprocessing device. In some embodiments, configuring a processing devicemay include programming the processing device directly witharchitectural instructions. For example, processing devices such asfield-programmable gate arrays (FPGAs), application-specific integratedcircuits (ASICs), and the like may be configured using, for example, oneor more hardware description languages (HDLs).

Vehicle 3700 may also include memory 3702 that may store instructionsfor various components of vehicle 3700. For example, memory 3702 maystore instructions that, when executed by processor 3701, may beconfigured to cause processor 3701 to perform one or more functions ofprocessor 3701 described herein. Memory 3702 may include any number ofrandom-access memories, read-only memories, flash memories, disk drives,optical storage, tape storage, removable storage, and other types ofstorage. In one instance, memory 3702 may be separate from processor3701. In another instance, memory 3702 may be integrated into processor3701. In some embodiments, memory 3702 may include software forperforming one or more computing tasks, as well as a trained system,such as a neural network, or a deep neural network.

Storage device 3703 may be configured to store various data andinformation for one or more components of vehicle 3700. Storage device3703 may include one or more hard drives, tapes, one or more solid-statedrives, any device suitable for writing and read data, or the like, or acombination thereof. For example, storage device 3703 may be configuredto store data of one or more maps. By way of example, storage device3703 may store data of a sparse map, which may include one or morelandmarks associated with a road segment and one or more targettrajectories associated with the road segment. As another example,storage device 3703 may be configured to store images captured by camera3706 and/or LIDAR data captured by LIDAR system 3707. Storage device3703 may also one or more images with correlated per-pixel depthinformation described in this disclosure.

Communications port 3704 may be configured to facilitate datacommunications between vehicle 3700 and other devices. For example,communications port 3704 may be configured to receive data from andtransmit data to a server (e.g., one or more servers described in thisdisclosure) via one or more public or private networks, including theInternet, an Intranet, a WAN (Wide-Area Network), a MAN(Metropolitan-Area Network), a wireless network compliant with the IEEE802.11a/b/g/n Standards, a leased line, or the like.

I/O device 3705 may be configured to receive input from the user ofvehicle 3700, and one or more components of vehicle 3700 may perform oneor more functions in response to the input received. In someembodiments, I/O device 3705 may include an interface displayed on atouchscreen. I/O device 3705 may also be configured to outputinformation and/or data to the user. For example, I/O device 3705 mayinclude a display configured to display a map.

Camera 3706 may be configured to capture one or more images of theenvironment of vehicle 3700. In some embodiments, camera 3706 mayinclude an image sensor with a global shutter, an image sensor with arolling shutter, or the like, or a combination thereof. For example, aCMOS image sensor may be employed along with a rolling shutter, suchthat each pixel in a row is read one at a time, and scanning of the rowsproceeds on a row-by-row basis until an entire image frame has beencaptured. In some embodiments, the rows may be captured sequentiallyfrom top to bottom relative to the frame. The use of a rolling shuttermay result in pixels in different rows being exposed and captured atdifferent times, which may cause skew and other image artifacts in thecaptured image frame. On the other hand, when camera 3706 is configuredto operate with a global or synchronous shutter, all of the pixels maybe exposed for the same amount of time and during a common exposureperiod. As a result, the image data in a frame collected from a systememploying a global shutter represents a snapshot of the entire FOV at aparticular time. In contrast, in a rolling shutter application, each rowin a frame is exposed and data is capture at different times. Thus,moving objects may appear distorted in an image capture device having arolling shutter. This phenomenon is described in greater detailelsewhere in this disclosure. In some embodiments, camera 3706 mayinclude a plurality of cameras configured to capture images of theenvironment of vehicle 3700. While the descriptions below are providedwith reference to a camera, one skilled in the art will understand thatthe disclosed systems and methods may also be implemented using two ormore cameras.

LIDAR system 3707 may include one or more LIDAR units. In someembodiments, the one or more LIDAR units may be positioned on a roof ofvehicle 3700. Such a unit may include a rotating unit configured togather LIDAR reflection information within a 360-degree field of viewaround vehicle 3700 or from any sub-segment of the 360-degree field ofview (e.g., one or more FOVs each representing less than 360 degrees).In some embodiments, a LIDAR unit may be positioned at a forwardlocation on vehicle 3700 (e.g., near the headlights, in the front grill,near the fog lamps, in a forward bumper, or at any other suitablelocation). In some cases, one or more LIDAR units installed on a forwardportion of vehicle 3700 may collect reflection information from a fieldof view in an environment forward of vehicle 3700. The data collected byLIDAR system 3707 may be provided to processor 3701. Alternatively oradditionally, the data may be transmitted to a server described in thisdisclosure via a network.

Any suitable type of LIDAR unit may be included on vehicle 3700. In somecases, LIDAR system 3707 may include one or more flash (also referred toherein as static) LIDAR units (e.g., 3D flash LIDAR) where an entireLIDAR field of view (FOV) is illuminated with a single laser pulse, anda sensor including rows and columns of pixels to record returned lightintensity and time of flight/depth information. Such flash systems mayilluminate a scene and collect LIDAR “images” multiple times per second.Accordingly, for a static LIDAR system, the whole set of LIDAR data of aLIDAR “image” may have the same timestamp. Scanning LIDAR units may alsobe employed. Such scanning LIDAR units may rely on one or moretechniques for dispersing a laser beam over a particular FOV. In somecases, a scanning LIDAR unit may include a scanning mirror that deflectsand directs a laser beam toward objects within the FOV. Scanning mirrorsmay rotate through a full 360 degrees or may rotate along a single axisor multiple axes over less than 360 degrees to direct the laser toward apredetermined FOV. In some cases, LIDAR units may scan one horizontalline. In other cases, a LIDAR unit may scan multiple horizontal lineswithin an FOV, effectively rastering a particular FOV multiple times persecond. In some embodiments, for a scanning LIDAR system, each scan linemay be acquired at a different time and thus have a different timestamp.

The LIDAR units in LIDAR system 3707 may include any suitable lasersource. In some embodiments, the LIDAR units may employ a continuouslaser. In other cases, the LIDAR units may use pulsed laser emissions.Additionally, any suitable laser wavelength may be employed. In somecases, a wavelength of between about 600 nm to about 1000 nm may beused.

The LIDAR unit(s) in LIDAR system 3707 may also include any suitabletype of sensor and provide any suitable type of output. In some cases,sensors of the LIDAR units may include solid state photodetectors, suchas one or more photodiodes or photomultipliers. The sensors may alsoinclude one or more CMOS or CCD devices including any number of pixels.These sensors may be sensitive to laser light reflected from a scenewithin the LIDAR FOV. The sensors may enable various types of outputfrom a LIDAR unit. In some cases, a LIDAR unit may output raw lightintensity values and time of flight information representative of thereflected laser light collected at each sensor or at each pixel orsub-component of a particular sensor. Additionally or alternatively, aLIDAR unit may output a point cloud (e.g., a 3D point cloud) that mayinclude light intensity and depth/distance information relative to eachcollected point). LIDAR units may also output various types of depthmaps representative of light reflection amplitude and distance to pointswithin a field of view. LIDAR units may provide depth or distanceinformation relative to particular points within an FOV by noting a timeat which light from the LIDAR's light source was initially projectedtoward the FOV and recording a time at which the incident laser light isreceived by a sensor in the LIDAR unit. The time difference mayrepresent a time of flight, which may be directly related to the roundtrip distance that the incident laser light traveled from the lasersource to a reflecting object and back to the LIDAR unit. Monitoring thetime of flight information associated with individual laser spots orsmall segments of a LIDAR FOV may provide accurate distance informationfor a plurality of points within the FOV (e.g., mapping to even verysmall features of objects within the FOV). In some cases, LIDAR unitsmay output more complex information, such as classification informationthat correlates one or more laser reflections with a type of object fromwhich the laser reflection was acquired.

Navigation system 3708 may be configured to assist a driver of vehicle3700 to operate vehicle 3700. For example, navigation system 3708 maydetermine that vehicle 3700 is currently deviating from a targettrajectory and generate a notification to the driver indicating thedeviation from the target trajectory, which may be displayed on adisplay (e.g., displaying the target trajectory and an estimated travelpath determined based on vehicle 3700's current position and headingdirection). Alternatively, navigation system 3708 may include anautonomous vehicle navigation system configured to control the movementof vehicle 3700, as described elsewhere in this disclosure. For example,navigation system 3708 may implement a navigation action determined byprocessor 3701 as vehicle 3700 traverses a road segment (e.g., one ormore of steering, braking, or acceleration of the vehicle). In someembodiments, navigation system 3708 may include an advanceddriver-assistance system (ADAS) system. In some embodiments, navigationsystem 3708 may be configured to cause activation of one or moreactuators associated with a steering system, a braking system, or adrive system of vehicle 3700 according to one or more navigationalactions.

In some embodiments, vehicle 3700 may also include one or more sensorsconfigured to collect information relating to vehicle 3700 and/or theenvironment of vehicle 3700. Exemplary sensors may include a positioningdevice (e.g., a Global Positioning System (GPS) device), anaccelerometer, a gyro sensor, a speedometer, or the like, or acombination thereof. For example, vehicle 3700 may include a GPS deviceconfigured to collect positioning data associated with positions ofvehicle 3700 over a period of time.

FIG. 38 is a flowchart showing an exemplary process 3800 for determininga navigational action for a host vehicle consistent with disclosedembodiments. Reference is also made to FIGS. 39A and 39B, which areschematic illustrations of exemplary point cloud information and images.While process 3800 is described below using vehicle 3700 as an example,one skilled in the art would understand that a server (e.g., one or moreservers described in this disclosure) can also be configured to performone or more steps of process 3800. For example, vehicle 3700 maytransmit an image captured by camera 3706 and LIDAR data captured byLIDAR system 3707 to a server via a network. The server may beconfigured to correlate the LIDAR data with the image to provideper-pixel depth information for one or more regions of the image. Theserver may also be configured to transmit the per-pixel depthinformation to vehicle 3700 for further processing.

At step 3801, processor 3701 may be programmed to receive from camera3706 at least one captured image representative of an environment ofvehicle 3700. For example, camera 3706 may be configured to capture animage 3921 illustrated in FIG. 39A at a first time point (or over afirst time period if the image is captured by a rolling shutter camera).Camera 3706 may also be configured to capture an image 3922 illustratedin FIG. 39B at a second time point after the first time point (or over asecond time period after the first time period if the image is capturedby a rolling shutter camera).

In some embodiments, as described above, camera 3706 may include aglobal shutter camera (i.e., a camera equipped with an image sensor witha global shutter). When camera 3706 is configured to operate with aglobal or synchronous shutter, all of the pixels may be exposed for thesame amount of time and during a common exposure period. As a result,all of the pixels in a frame collected from a global shutter cameraemploying may have a same timestamp. Alternatively or additionally,camera 3706 may include a rolling shutter camera (i.e., a cameraequipped with an image sensor with a rolling shutter). For example,camera 3706 may include a camera having a rolling shutter, such thateach pixel in a row may read one at a time, and scanning of the rowsproceeds on a row-by-row basis until an entire image frame has beencaptured. In some embodiments, the rows may be captured sequentiallyfrom top to bottom (or from bottom to top) relative to the frame.Accordingly, the image data of one row may have a timestamp differentfrom the image data of another row.

In some embodiments, processor 3701 may be programmed to receiveinformation of the capture time of each pixel of an image from camera3706. For example, for an image captured by a global shutter camera, thecapture time may be the same for all pixels, and processor 3701 mayobtain the capture time from camera 3706. For an image captured by arolling shutter camera, in some embodiments, at least some row(s) of theimage may have a capture time different from that of other rows.Processor 3701 may obtain the capture time for each of the rows of theimage from camera 3706.

Referring to FIG. 38 , at step 3802, processor 3701 may be programmed toreceive point cloud information from a LIDAR system onboard the hostvehicle. The point cloud information may be representative of distancesto various objects in the environment of vehicle 3700. LIDAR system 3707may capture reflection information from its field of view in theenvironment of vehicle 3700. The reflection information may includeinformation relating to reflections by various objects in the field ofview. For example, LIDAR system 3707 may capture reflection informationfrom various objects in its field of view at a third time point if theLIDAR data is captured by a static LIDAR system (or over a third timeperiod the LIDAR data is captured by a scanning LIDAR system), which maybe represented by a point cloud “image” 3911 illustrated in FIG. 39A.LIDAR system 3707 may capture reflection information from variousobjects in its field of view at a fourth time point after the third timepoint if the LIDAR data is captured by the static LIDAR system (or overa fourth time period after the third time period the LIDAR data iscaptured by a scanning LIDAR system), which may be represented by apoint cloud “image” 3912 illustrated in FIG. 39B.

In some embodiments, processor 3701 may be programmed to obtain receiveinformation of the capture time of each point of the point cloudinformation from LIDAR system 3707. For example, for point cloudinformation captured by a static LIDAR system, the capture time may bethe same for all points of the point cloud information, and processor3701 may obtain the capture time from LIDAR system 3707 and use theobtained capture time for all the points in the point cloud information.For point cloud information captured by a scanning LIDAR system, in someembodiments, at least some line(s) of points in the point cloudinformation may have a capture time different from that of other lines.For example, as described elsewhere in this disclosure, LIDAR system3707 may include a scanning LIDAR system configured to one horizontalline at a time, and the points of each line of the point cloudinformation captured by the scanning LIDAR system may have a differentcapture time. As another example, LIDAR system 3707 may include ascanning LIDAR system configured to scan multiple horizontal lines (andreferred to herein as a scanning group of lines) within an FOV at atime, and the points of each scanning group of lines may have adifferent capture time than that of other groups of lines. Processor3701 may obtain a capture time of each line (or a capture time of eachscanning group of lines) from LIDAR system 3707.

In some embodiments, the point cloud information may be accumulatedbased on LIDAR data over a period of time (e.g., LIDAR data capturedover multiple frames). For example, LIDAR system 3707 may capture aplurality of frames and generate point cloud information by accumulatingLIDAR data of the frames (e.g., accumulating depth information of theframes). Alternatively, processor 3701 may be programmed to receiveLIDAR data of the frames and accumulate the LIDAR data to generate pointcloud information, which may provide a dense point cloud.

In some embodiments, the point cloud information may be acquired at thesame time point when the image was captured. In other embodiments, priorto (or after) the timestamp at which the captured image was acquired.For example, point cloud “image” 3911 may be acquired prior to (orafter) the timestamp at which image 3921. Alternatively, some of thepoint cloud information was acquired prior to the timestamp at which theat least one captured image was acquired and some of the point cloudinformation was acquired after the timestamp at which the at least onecaptured image was acquired. For example, for point cloud informationcaptured by a scanning LIDAR system, which may scan a horizontal line ata time, some of the lines may be captured at prior to the timestamp atwhich the captured image was acquired, and the other lines may becaptured after the timestamp at which the captured image was acquired.

Referring to FIG. 38 , at step 3803, processor 3701 may be programmed tocorrelate the point cloud information with the at least one capturedimage to provide per-pixel depth information for one or more regions ofthe at least one captured image. For example, processor 3701 may beprogrammed to identify a region in the point cloud informationcorresponding to a region of the image and map the points of the regionin the point cloud information to the corresponding pixels of the regionof the image by, for example, assigning the depth information of thepoints to the corresponding pixels in the image.

In some embodiments, processor 3701 may adjust the region in the pointcloud information and/or the corresponding region of the image beforecorrelating the depth information with the pixels of the image. Forexample, processor 3701 may stretch or shrink one or more regions of theimage to fit the corresponding regions of the point cloud informationbefore correlating depth information of the point cloud information withthe image.

In some embodiments, the capture times of the point cloud informationand the image may be different. Processor 3701 may be programmed to warp(or map) the point cloud information to a timestamp at which thecaptured image was acquired. For example, LIDAR system 3707 may capturethe point cloud information at a first capture time, and the point cloudinformation may include a first timestamp. Camera 3706 may capture theimage at the second capture time after the first capture time. The imagemay include a second timestamp. Processor 3701 may correlate the depthinformation of the point cloud information with the image. In someembodiments, the first and second timestamps may be the same ordifferent.

In some embodiments, processor 3701 may select one of multiple sets ofpoint cloud information to correlate with an image. For example, when nopoint cloud information has the same capture time as an image to becorrelated, processor 3701 may select the point cloud information havinga capture time that is the closest to the capture time of the image andcorrelate the depth information of the selected point cloud informationwith the image to provide a per-pixel depth information for one or moreregions of the image. Alternatively or additionally, processor 3701 maydetermine an estimated set of point cloud information based on two setsof point cloud information and correlate the depth information of theestimated set of point cloud information with the image. For example,processor 3701 may obtain a first set of point cloud information thatwas acquired before the image was acquired and obtain a second set ofpoint cloud information that was acquired after the image was acquired.Processor 3701 may determine an estimated (or interpolated) set of pointcloud information (by, e.g., average the depths of the two sets of pointcloud information to obtain an average depth at each point). Processor3701 may also correlate the depth information of the estimated set ofpoint cloud information with the image.

In some embodiments, when the first and second timestamps are different,in correlating depth information of the point cloud information with theimage, processor 3701 may account for ego motion of vehicle 3700. Insome instances, a direct correlation of the depth information of thepoint cloud information with the image may not be accurate if the pointcloud information and the image were acquired at different times.Processor 3701 may determine the ego motion over the time period betweenthe capture time of the point cloud information and the capture time ofthe image, and adjust the depth information of the point cloudinformation accordingly. For example, processor 3701 may be programmedto add (or subtract) a distance or depth caused by the ego motion ofvehicle 3700 (over the time period between the capture times of thepoint cloud information and the image) to the depth information of thepoint cloud information representing objects in the moving direction ofvehicle 3700. In some embodiments, processor 3701 may determine the egomotion of vehicle 3700 based on an output of one or more sensorsrepresenting the position change over the time period between thecapture times of the point cloud information and the image. For example,vehicle 3700 may include one or more sensors (e.g., at least one of aspeedometer, an accelerometer, or a GPS sensor) configured to track theposition of vehicle 3700 over the time period. Processor 3701 maydetermine the ego motion of vehicle 3700 over the time period based onthe output from the one or more sensors. Alternatively or additionally,processor 3701 may determine the ego motion based on an optical flow ofobjects observed between two or more images captured by camera 3706. Forexample, processor 3701 may compare the location of a non-moving object(e.g., a light pole) in a first image with the location of thenon-moving object in a second image to determine the ego motion ofvehicle 3700. In some embodiments, processor 3701 may determine the egomotion based on a combination of an optical flow of objects observedbetween two or more images captured by camera 3706 and an output of oneor more sensors associated with vehicle 3700.

In some embodiments, the ego motion of vehicle 3700 may be determinedbased on one or more methods described as described elsewhere in thisdisclosure (e.g., one or more methods for determining an ego motion of ahost vehicle provided in connection with FIG. 31 and the descriptionsthereof).

At step 3804, processor 3701 may be programmed to determine at least onenavigational action for vehicle 3700 based on the per-pixel depthinformation for one or more regions of the at least one captured image.Exemplary navigational actions may include at least one of maintaining acurrent heading direction and speed for vehicle 3700, changing a currentheading direction for vehicle 3700, or changing a speed of vehicle 3700.For example, processor 3701 may analyze the one or more regions of theat least one captured image and the per-pixel depth information for theone or more regions of the at least one captured image to identify anobject that is within a predetermined safety distance. Processor 3701may also be configured to determine a navigational action for vehicle3700 to slow vehicle 3700 or steer away from the identified object.

At step 3805, processor 3701 may be programmed to cause the at least onenavigational action to be taken by vehicle 3700. For example, processor3701 may be programmed to cause the at least one navigational action tobe taken by vehicle 3700 by causing activation of one or more actuatorsassociated with a steering system (e.g., maintaining or changing acurrent heading direction), a braking system (e.g., reducing a currentspeed) or a drive system of vehicle 3700 (e.g., accelerating,deaccelerating, reducing a current speed).

LIDAR-Camera Fusion where LIDAR and Camera Validly Detect DifferentThings

In some cases, a host vehicle may be equipped with a LIDAR system and acamera. The LIDAR system and the camera may have different fields ofview and capture different scene information from the environment of thehost vehicle due to differences in physical location relative to thehost vehicle. For example, the LIDAR system may be located on a roof ofthe host vehicle, and a camera may be located behind the windshield. Asa result, in some instances, the LIDAR system may detect an object(e.g., a target vehicle) that the camera does not capture (e.g., theobject may be obscured by a vehicle immediately ahead of the hostvehicle). These differences can cause problems when the system attemptsto align the sensed information by the LIDAR system with the sensedinformation by the camera, which may lead to a possibility of discardingsuch information as potentially erroneous. This disclosure providessystems and methods for determining a potential action that the hostvehicle may take when a difference between the sensed information by theLIDAR system and the sensed information by the camera is detected. Forexample, if the LIDAR and/or camera detects a vehicle immediately aheadof the host, then it may be understood that this vehicle may obscureobjects further forward within a region that only a higher-mounted LIDARsystem can detect. In such cases, the disclosed systems and methods mayuse information collected by the LIDAR system and the camera to detectan object and determine what action the host vehicle may take inresponse to the detection of the object.

FIG. 40 illustrates an exemplary vehicle 4000 consistent with disclosedembodiments. The disclosed systems and methods may be implemented usingone or more components of vehicle 4000. As illustrated in FIG. 40 ,vehicle 4000 may include at least one processor (e.g., processor 4001),a memory 4002, at least one storage device (e.g., storage device 4003),a communications port 4004, an I/O device 4005, a camera 4006, a LIDARsystem 4007, and a navigation system 4008.

Processor 4001 may be programmed to perform one or more functions ofvehicle 4000 described in this disclosure. Processor 4001 may include amicroprocessor, preprocessors (such as an image preprocessor), agraphics processing unit (GPU), a central processing unit (CPU), supportcircuits, digital signal processors, integrated circuits, memory, or anyother types of devices suitable for running applications or performing acomputing task. In some embodiments, processor 4001 may include any typeof single or multi-core processor, mobile device microcontroller,central processing unit, etc. Various processing devices may be used,including, for example, processors available from manufacturers such asIntel®, AMD®, etc., or GPUs available from manufacturers such asNVIDIA®, ATI®, etc. and may include various architectures (e.g., x86processor, ARM®, etc.). Any of the processing devices disclosed hereinmay be configured to perform certain functions. Configuring a processingdevice, such as any of the described processors or other controller ormicroprocessor, to perform certain functions may include programming ofcomputer-executable instructions and making those instructions availableto the processing device for execution during operation of theprocessing device. In some embodiments, configuring a processing devicemay include programming the processing device directly witharchitectural instructions. For example, processing devices such asfield-programmable gate arrays (FPGAs), application-specific integratedcircuits (ASICs), and the like may be configured using, for example, oneor more hardware description languages (HDLs).

Vehicle 4000 may also include a memory 4002 that may store instructionsfor various components of vehicle 4000. For example, memory 4002 maystore instructions that, when executed by processor 4001, may beconfigured to cause processor 4001 to perform one or more functions ofprocessor 4001 described herein. Memory 4002 may include any number ofrandom-access memories, read-only memories, flash memories, disk drives,optical storage, tape storage, removable storage, and other types ofstorage. In one instance, memory 4002 may be separate from processor4001. In another instance, memory 4002 may be integrated into processor4001. In some embodiments, memory 4002 may include software forperforming one or more computing tasks, as well as a trained system,such as a neural network, or a deep neural network.

Storage device 4003 may be configured to store various data andinformation for one or more components of vehicle 4000. Storage device4003 may include one or more hard drives, tapes, one or more solid-statedrives, any device suitable for writing and read data, or the like, or acombination thereof. For example, storage device 4003 may be configuredto store data of one or more maps. By way of example, storage device4003 may store data of a sparse map, which may include one or morelandmarks associated with a road segment and one or more targettrajectories associated with the road segment. As another example,storage device 4003 may be configured to store images captured by camera4006 and/or LIDAR data captured by LIDAR system 4007.

Communications port 4004 may be configured to facilitate datacommunications between vehicle 4000 and other devices. For example,communications port 4004 may be configured to receive data from andtransmit data to a server (e.g., one or more servers described in thisdisclosure) via one or more public or private networks, including theInternet, an Intranet, a WAN (Wide-Area Network), a MAN(Metropolitan-Area Network), a wireless network compliant with the IEEE802.11a/b/g/n Standards, a leased line, or the like.

I/O device 4005 may be configured to receive input from the user ofvehicle 4000, and one or more components of vehicle 4000 may perform oneor more functions in response to the input received. In someembodiments, I/O device 4005 may include an interface displayed on atouchscreen. I/O device 4005 may also be configured to outputinformation and/or data to the user. For example, I/O device 4005 mayinclude a display configured to display a map.

Camera 4006 may be configured to capture one or more images of theenvironment of vehicle 4000. Camera 4006 may include any type of devicesuitable for capturing at least one image from an environment. In someembodiments, camera 4006 may be similar to image capture devices 122,124, and 126 illustrated in FIG. 1 and described above. In someembodiments, camera 4006 may include a plurality of cameras configuredto capture images of the environment of vehicle 4000. While thedescriptions below are provided with reference to a camera, one skilledin the art will understand that the disclosed systems and methods mayalso be implemented using two or more cameras.

Camera 4006 may be positioned at any suitable location on vehicle 4000.For example, camera 4006 may be located behind a windshield of vehicle4000, in a vicinity of a front bumper of vehicle 4000, a vicinity of therearview mirror of vehicle 4000, one or both of the side mirrors ofvehicle 4000, on the roof of vehicle 4000, on the hood of vehicle 4000,on the trunk of vehicle 4000, on the sides of vehicle 4000, mounted on,positioned behind, or positioned in front of any of the windows ofvehicle 4000, and mounted in or near light figures on the front and/orback of vehicle 4000, etc.

LIDAR system 4007 may include one or more LIDAR units. In someembodiments, the one or more LIDAR units may be positioned on a roof ofvehicle 4000. Such a unit may include a rotating unit configured togather LIDAR reflection information within a 360-degree field of viewaround vehicle 4000 or from any sub-segment of the 360-degree field ofview (e.g., one or more FOVs each representing less than 360 degrees).The data collected by LIDAR system 4007 may be provided to processor4001. Alternatively or additionally, the data may be transmitted to aserver described in this disclosure via a network.

In some embodiments, a LIDAR unit may be positioned at a forwardlocation on vehicle 4000 (e.g., near the headlights, in the front grill,near the fog lamps, in a forward bumper, or at any other suitablelocation). In some cases, one or more LIDAR units installed on a forwardportion of vehicle 4000 may collect reflection information from a fieldof view in an environment forward of vehicle 4000. In other embodiments,a LIDAR unit may be located in other locations. For example, a LIDARunit may be located behind a windshield of vehicle 4000, in a vicinityof a front bumper of vehicle 4000, a vicinity of the rearview mirror ofvehicle 4000, one or both of the side mirrors of vehicle 4000, on theroof of vehicle 4000, on the hood of vehicle 4000, on the trunk ofvehicle 4000, on the sides of vehicle 4000, mounted on, positionedbehind, or positioned in front of any of the windows of vehicle 4000,and mounted in or near light figures on the front and/or back of vehicle4000, etc.

In some embodiments, LIDAR system 4007 may be located in a locationdifferent from a location of camera 4006. For example, camera 4006 maybe located behind a windshield of vehicle 4000, and LIDAR system 4007may be mounted on a roof of vehicle 4000. As another example, camera4006 be located in a vicinity of a front bumper of vehicle 4000, andLIDAR system 4007 is mounted on a roof of vehicle 4000. As anotherexample, camera 4006 be located behind a windshield of vehicle 4000, andLIDAR system 4007 be located in a vicinity of a front bumper of vehicle4000. In some embodiments, camera 4006 may have an FOV different fromthe FOV of LIDAR system 4007, but the FOV of camera 4006 may at leastpartially overlap with a FOV of LIDAR system 4007 to provide a sharedfield of view region.

Any suitable type of LIDAR unit may be included in vehicle 4000. In somecases, LIDAR system 4007 may include one or more flash (also referred toherein as static) LIDAR units (e.g., 3D flash LIDAR) where an entireLIDAR field of view (FOV) is illuminated with a single laser pulse, anda sensor including rows and columns of pixels to record returned lightintensity and time of flight/depth information. Such flash systems mayilluminate a scene and collect LIDAR “images” multiple times per second.Scanning LIDAR units may also be employed. Such scanning LIDAR units mayrely on one or more techniques for dispersing a laser beam over aparticular FOV. In some cases, a scanning LIDAR unit may include ascanning mirror that deflects and directs a laser beam toward objectswithin the FOV. Scanning mirrors may rotate through a full 360 degreesor may rotate along a single axis or multiple axes over less than 360degrees to direct the laser toward a predetermined FOV. In some cases,LIDAR units may scan one horizontal line. In other cases, a LIDAR unitmay scan multiple horizontal lines within an FOV, effectively rasteringa particular FOV multiple times per second.

The LIDAR units in LIDAR system 4007 may include any suitable lasersource. In some embodiments, the LIDAR units may employ a continuouslaser. In other cases, the LIDAR units may use pulsed laser emissions.Additionally, any suitable laser wavelength may be employed. In somecases, a wavelength of between about 600 nm to about 1000 nm may beused.

The LIDAR unit(s) in LIDAR system 4007 may also include any suitabletype of sensor and provide any suitable type of output. In some cases,sensors of the LIDAR units may include solid state photodetectors, suchas one or more photodiodes or photomultipliers. The sensors may alsoinclude one or more CMOS or CCD devices including any number of pixels.These sensors may be sensitive to laser light reflected from a scenewithin the LIDAR FOV. The sensors may enable various types of outputfrom a LIDAR unit. In some cases, a LIDAR unit may output raw lightintensity values and time of flight information representative of thereflected laser light collected at each sensor or at each pixel orsub-component of a particular sensor. Additionally or alternatively, aLIDAR unit may output a point cloud (e.g., a 3D point cloud) that mayinclude light intensity and depth/distance information relative to eachcollected point). LIDAR units may also output various types of depthmaps representative of light reflection amplitude and distance to pointswithin a field of view. LIDAR units may provide depth or distanceinformation relative to particular points within an FOV by noting a timeat which light from the LIDAR's light source was initially projectedtoward the FOV and recording a time at which the incident laser light isreceived by a sensor in the LIDAR unit. The time difference mayrepresent a time of flight, which may be directly related to the roundtrip distance that the incident laser light traveled from the lasersource to a reflecting object and back to the LIDAR unit. Monitoring thetime of flight information associated with individual laser spots orsmall segments of a LIDAR FOV may provide accurate distance informationfor a plurality of points within the FOV (e.g., mapping to even verysmall features of objects within the FOV). In some cases, LIDAR unitsmay output more complex information, such as classification informationthat correlates one or more laser reflections with a type of object fromwhich the laser reflection was acquired.

Navigation system 4008 may be configured to assist a driver of vehicle4000 to operate vehicle 4000. For example, navigation system 4008 maydetermine that vehicle 4000 is currently deviating from a targettrajectory and generate a notification to the driver indicating thedeviation from the target trajectory, which may be displayed on adisplay (e.g., displaying the target trajectory and an estimated travelpath determined based on vehicle 4000's current position and headingdirection). Alternatively, navigation system 4008 may include anautonomous vehicle navigation system configured to control the movementof vehicle 4000, as described elsewhere in this disclosure. For example,navigation system 4008 may implement a navigation action determined byprocessor 4001 as vehicle 4000 traverses a road segment (e.g., one ormore of steering, braking, or acceleration of the vehicle). In someembodiments, navigation system 4008 may include an advanceddriver-assistance system (ADAS) system. In some embodiments, navigationsystem 4008 may be configured to cause activation of one or moreactuators associated with a steering system, a braking system, or adrive system of vehicle 4000 according to one or more navigationalactions.

In some embodiments, vehicle 4000 may also include one or more sensorsconfigured to collect information relating to vehicle 4000 and/or theenvironment of vehicle 4000. Exemplary sensors may include a positioningdevice (e.g., a Global Positioning System (GPS) device), anaccelerometer, a gyro sensor, a speedometer, or the like, or acombination thereof. For example, vehicle 4000 may include a GPS deviceconfigured to collect positioning data associated with positions ofvehicle 4000 over a period of time.

FIG. 41 is a flowchart showing an exemplary process 4100 for determininga navigational action for a host vehicle consistent with disclosedembodiments. Reference is also made to FIG. 42 , which is a schematicillustration of an exemplary environment of vehicle 4000.

At step 4101, processor 4001 may be programmed to receive from camera4006 onboard vehicle 4000 at least one captured image representative ofan environment of vehicle 4000. In some embodiments, camera 4006 may beconfigured to capture one or more images presentative of the environmentof vehicle 4000 similar to one or more processes for capturing images asdescribed elsewhere in this disclosure.

Camera 4006 may be positioned at a first location relative to vehicle4000. For example, camera 4006 may be located behind a windshield ofvehicle 4000, in a vicinity of a front bumper of vehicle 4000, avicinity of the rearview mirror of vehicle 4000, one or both of the sidemirrors of vehicle 4000, on the roof of vehicle 4000, on the hood ofvehicle 4000, on the trunk of vehicle 4000, on the sides of vehicle4000, mounted on, positioned behind, or positioned in front of any ofthe windows of vehicle 4000, and mounted in or near light figures on thefront and/or back of vehicle 4000, etc. By way of example, asillustrated in FIG. 42 , camera 4006 may be located in a vicinity of thefront bumper of vehicle 4000.

In some embodiments, camera 4006 may be configured to capture aplurality of captured images over a period of time, which may indicatethe movement of vehicle 4000 relative to one or more objects in theenvironment (e.g., deacceleration of a leading vehicle).

Referring to FIG. 41 , at step 4102, processor 4001 may be programmed toreceive point cloud information from a LIDAR system onboard the hostvehicle. As described elsewhere in this disclosure, point cloudinformation may be representative of distances to various objects in theenvironment of the host vehicle. LIDAR system 4007 may capturereflection information from its field of view in the environment ofvehicle 4000. The reflection information may include informationrelating to reflections by various objects in the field of view. In someembodiments, the point cloud information may include multiple, capturedLIDAR frames. A LIDAR frame may refer to LIDAR data captured during ascanning cycle. In one example, a typical frame-time may last less thana second. In some embodiments, LIDAR system 4007 may have a fixed framerate (e.g. 10 frames per second, 25 frames per second, 50 frames persecond) or the frame rate may be dynamic. Similar to a series of imagescaptured by camera 4006 over a period of time described above, multiple,captured LIDAR frames may also be used by processor 4001 to determinethe movement of vehicle 4000 relative to one or more objects in theenvironment (e.g., deacceleration of a leading vehicle).

In some embodiments, LIDAR system 4007 may be positioned at a secondlocation relative to vehicle 4000. For example, LIDAR system 4007 may bepositioned at a forward location on vehicle 4000 (e.g., near theheadlights, in the front grill, near the fog lamps, in a forward bumper,or at any other suitable location). In some cases, LIDAR system 4007installed on a forward portion of vehicle 4000 may collect reflectioninformation from a field of view in an environment forward of vehicle4000. In other embodiments, LIDAR system 4007 may be located in otherlocations. For example, LIDAR system 4007 may be located behind awindshield of vehicle 4000, in a vicinity of a front bumper of vehicle4000, a vicinity of the rearview mirror of vehicle 4000, one or both ofthe side mirrors of vehicle 4000, on the roof of vehicle 4000, on thehood of vehicle 4000, on the trunk of vehicle 4000, on the sides ofvehicle 4000, mounted on, positioned behind, or positioned in front ofany of the windows of vehicle 4000, and mounted in or near light figureson the front and/or back of vehicle 4000, etc.

In some embodiments, the second location (at which LIDAR system 4007 ispositioned) and the first location (at which camera 4006 is positioned)may be different. For example, camera 4006 may be located behind awindshield of vehicle 4000, and LIDAR system 4007 may be mounted on aroof of vehicle 4000. As another example, camera 4006 be located in avicinity of a front bumper of vehicle 4000, and LIDAR system 4007 ismounted on a roof of vehicle 4000. As another example, camera 4006 belocated behind a windshield of vehicle 4000, and LIDAR system 4007 belocated in a vicinity of a front bumper of vehicle 4000. In someembodiments, camera 4006 may have an FOV different from the FOV of LIDARsystem 4007, but the FOV of camera 4006 may at least partially overlapwith a FOV of LIDAR system 4007 to provide a shared field of viewregion. In some embodiments, a field of view of camera 4006 may at leastpartially overlap with a field of view of LIDAR system 4007 to provide ashared field of view region. By way of example, as illustrated in FIG.42 , camera 4006 is located in a vicinity of a front bumper of vehicle4000, and LIDAR system 4007 is mounted on a roof of vehicle 4000. LIDARsystem 4007 has a LIDAR FOV 4017, and camera 4006 has a camera FOV 4016,which may at least partially overlap with a field of view of LIDARsystem 4007 to provide a shared FOV region 4018. A shared FOV region mayrefer to a region that both camera 4006 and LIDAR system 4007 may sense,but their vantage point difference may lead to differences in what theycan detect in the shared FOV region. By way of example, as illustratedin FIG. 42 , a lower positioned camera 4006 (e.g., located in thevicinity of the front bumper of vehicle 4000) may sense only one leadingvehicle (e.g., first vehicle 4201), but a higher positioned LIDAR system4007 (e.g., located on the roof of vehicle 4000) may sense an objectbeyond the leading vehicle (e.g., second vehicle 4202). In anotherexample, on the other hand, a camera positioned in the grill of the hostvehicle may sense objects very close to the host vehicle (e.g., object4211 on the ground illustrated in FIG. 42 , where a LIDAR system mountedon the roof of the host vehicle may be obscured by the hood of the hostvehicle. As another example, a LIDAR system may have a better view ofcloser objects that may be obscured from the captured camera images bythe hood of the host vehicle.

Referring to FIG. 41 , at step 4103, processor 4001 may be programmed toanalyze the at least one captured image and the received point cloudinformation to detect one or more objects in the shared field of viewregion (e.g., shared FOV region 4018 illustrated in FIG. 42 ). Thedetected one or more objects may be represented in only one of the atleast one captured image or the received point cloud information. By wayof example, as illustrated in FIG. 42 , processor 4001 may be programmedto analyze the at least one captured image and the received point cloudinformation and detect an object 4211 on the ground, which may be inshared FOV region 4018. Object 4211, however, may appear in the at leastone captured image, but not in the point cloud information, given thatthe view of LIDAR system 4007 the LIDAR may be obscured by the hood ofvehicle 4000. In some embodiments, a detected object by processor 4001at step 4103 may include an object located ahead of a target vehicleforward of the host vehicle. In one example, as illustrated in FIG. 42 ,although second vehicle 4202 may also appear in camera FOV 4016 (andsecond vehicle 4202), second vehicle 4202 is blocked from the view ofcamera 4006 by first vehicle 4201 (i.e., the leading vehicle or a targetvehicle). As a result, second vehicle 4202 may appear in the point cloudinformation, but not in the one or more captured images. a detectedobject by processor 4001 at step 4103 may include a static object in aroadway (e.g., a speed bump on the roadway). In some embodiments, adetected object by processor 4001 at step 4103 may include an objectlocated ahead of vehicle 4000 but close enough that a portion of vehicle4000 (e.g., the front of vehicle 4000) obscures the one or more objectsfrom either the at least one captured image or the point cloudinformation. By way of example, as illustrated in FIG. 42 , processor4001 may detect object 4211 on the ground that may be block by the hoodof vehicle 4000 and may only appear in the captured image.

At step 4104, processor 4001 may be programmed to determine whether avantage point difference between the first location of camera 4006 andthe second location of LIDAR system 4007 accounts for the one or moredetected objects being represented in only one of the at least onecaptured image or the received point cloud information. For example,processor 4001 may determine a vantage point difference based on theFOVs and/or the locations of camera 4006 and LIDAR system 4007.Processor 4001 may also determine whether the non-appearance of anobject (at step 4103) in one of the at least one captured image or thereceived point cloud information but not in the other is due to thevantage point difference.

If processor 4001 determines that the vantage point difference does notaccount for the one or more detected objects being represented in onlyone of the at least one captured image or the received point cloudinformation, then process 4100 proceeds to step 4105. At step 4105,processor 4001 may be programmed to cause at least one remedial actionto be taken. A remedial action may include at least one of issuing awarning to a passenger and/or a driver of vehicle 4000 (e.g., afterdetecting a speed bump on a roadway) or disregarding the one or moredetected objects in navigation of the host vehicle (e.g., afterdetecting a small object on the ground).

In some embodiments, the at least one remedial action may includeapplying different weights to an image-based detection path based onanalysis of the at least one captured image and a LIDAR-based detectionpath based on analysis of the point cloud information. In some cases, adifference in detection results by camera 4006 and LIDAR system may notbe due to a vantage point difference between camera 4006 and LIDARsystem 4007, but due to other reasons. For example, the difference indetection results may be due to certain environmental conditions. By wayof example, LIDAR system 4007 may perform better in a sun glareenvironment than (or a highly reflective environment, or a low lightcondition during a night time without street lights, etc.) camera 4006.As a result, processor 4001 may detect an object in the point cloudinformation, but not in the images captured by camera 4006 even if theobject appears in both views of camera 4006 and LIDAR system 4007. Onthe other hand, camera 4006 may perform better on a foggy or rainy daythan LIDAR system 4007. As a result, processor 4001 may detect an objectin the images, but not in the point cloud information. If processor 4001determines that the vantage point difference does not account for theone or more detected objects being represented in only one of the atleast one captured image or the received point cloud information,processor 4001 may apply different weights to an image-based detectionpath based on analysis of the at least one captured image and aLIDAR-based detection path based on analysis of the point cloudinformation. For example, if processor 4001 determines that thenon-detection of an object in the point cloud information is due to aweather condition (e.g., a rainy day), processor 4001 may apply a weightto an image-based detection path higher than that to a LIDAR-baseddetection path, which may give more an accurate detection result. Asanother example, if processor 4001 determines that the non-detection ofan object in the image(s) is due to lighting conditions (e.g., vehicle4000 is navigating during the night time without street lights),processor 4001 may apply a weight to an image-based detection path lowerthan that to a LIDAR-based detection path.

If processor 4001 determines that the vantage point difference doesaccount for the one or more detected objects being represented in onlyone of the at least one captured image or the received point cloudinformation, process 4100 may proceed to step 4106. At step 4106,processor 4001 may be programmed to determine at least one navigationalaction to be taken by vehicle 4000 based on the one or more detectedobjects and, at step 4107 cause the at least one navigational action tobe taken by vehicle 4000. As described elsewhere in this disclosure, anavigational action determined by a processor and taken by vehicle 4000may include maintaining or changing a current heading direction,increasing or reducing a current speed, or the like, or a combinationthereof. Processor 4001 may also be programmed to cause the at least onenavigational action to be taken by vehicle 4000 according to one or moremethods for controlling a navigation system described elsewhere in thisdisclosure. For example, processor 4001 may be programmed to cause theat least one navigational action to be taken by vehicle 4000 by causingactivation of one or more actuators associated with a steering system(e.g., maintaining or changing a current heading direction), a brakingsystem (e.g., reducing a current speed) or a drive system of vehicle4000 (e.g., accelerating, deaccelerating, reducing a current speed).

In some embodiments, processor 4001 may determine the at least onenavigational action based on a detected action or movement of thedetected object(s). For example, as described above, processor 4001 maydetect second vehicle 4202 illustrated in FIG. 42 (which is ahead offirst vehicle 4201, a target vehicle) in the point cloud informationcaptured by LIDAR system 4007. Processor 4001 may be programmed todetermine a navigational action based on a detected action of secondvehicle 4202 although first vehicle 4201. For example, processor 4001may be programmed to detect a slowing of second vehicle 4202 based on,for example, multiple LIDAR frames of point cloud information, althoughthe target vehicle is not detected to be slowing. Processor 4001 mayalso be programmed to determine a navigational action of braking vehicle4000. Processor 4001 may also be programmed to cause navigation system4008 to brake vehicle 4000.

Pseudo LIDAR

This disclosure provides systems and methods that may infer depthinformation in the pixels of images captured by one or more groups ofcameras. For example, in some embodiments, a host vehicle may include agroup of cameras, which may include three cameras, namely, a centercamera, a left surround camera, and a right surround camera. The FOV ofthe center camera may at least partially overlap with both a FOV of theleft surround camera and a FOV of the right surround camera. The centercamera may be configured to capture one or more images (also referred toherein as center images) of at least in a portion of the environment ofthe host vehicle in the FOV of the center camera. The left surroundcamera may be configured to capture one or more images (also referred toherein as left surround images) of at least in a portion of theenvironment of the host vehicle in the FOV of the left surround camera.The right surround camera may be configured to capture one or moreimages (also referred to herein as right surround images) of at least ina portion of the environment of the host vehicle in the FOV of the rightsurround camera. The host vehicle may receive a captured center imagefrom the center camera, a captured left surround image from the leftsurround camera, and a captured right surround image from the rightsurround camera. The host vehicle may also provide the received imagesto an analysis module, which may be configured to generate an outputrelative to the center image based on analysis of the center, leftsurround, and right surround images. In some embodiments, the generatedoutput may include per-pixel depth information for at least one regionof the center image. The host vehicle may further take at least onenavigational action based on the generated output including theper-pixel depth information for the at least one region of the centerimage.

FIG. 43 illustrates an exemplary vehicle 4300 consistent with disclosedembodiments. The disclosed systems and methods may be implemented usingone or more components of vehicle 4300. As illustrated in FIG. 43 ,vehicle 4300 may include at least one processor (e.g., processor 4301),memory 4302, at least one storage device (e.g., storage device 4303), acommunications port 4304, an I/O device 4305, a plurality of cameras4306, a LIDAR system 4307, and a navigation system 4308.

Processor 4301 may be programmed to perform one or more functions ofvehicle 4300 described in this disclosure. Processor 4301 may include amicroprocessor, preprocessors (such as an image preprocessor), agraphics processing unit (GPU), a central processing unit (CPU), supportcircuits, digital signal processors, integrated circuits, memory, or anyother types of devices suitable for running applications or performing acomputing task. In some embodiments, processor 4301 may include any typeof single or multi-core processor, mobile device microcontroller,central processing unit, etc. Various processing devices may be used,including, for example, processors available from manufacturers such asIntel®, AMD®, etc., or GPUs available from manufacturers such asNVIDIA®, ATI®, etc. and may include various architectures (e.g., x86processor, ARM®, etc.). Any of the processing devices disclosed hereinmay be configured to perform certain functions. Configuring a processingdevice, such as any of the described processors or other controller ormicroprocessor, to perform certain functions may include programming ofcomputer-executable instructions and making those instructions availableto the processing device for execution during operation of theprocessing device. In some embodiments, configuring a processing devicemay include programming the processing device directly witharchitectural instructions. For example, processing devices such asfield-programmable gate arrays (FPGAs), application-specific integratedcircuits (ASICs), and the like may be configured using, for example, oneor more hardware description languages (HDLs).

Vehicle 4300 may also include memory 4302 that may store instructionsfor various components of vehicle 4300. For example, memory 4302 maystore instructions that, when executed by processor 4301, may beconfigured to cause processor 4301 to perform one or more functions ofprocessor 4301 described herein. Memory 4302 may include any number ofrandom-access memories, read-only memories, flash memories, disk drives,optical storage, tape storage, removable storage, and other types ofstorage. In one instance, memory 4302 may be separate from processor4301. In another instance, memory 4302 may be integrated into processor4301. In some embodiments, memory 4302 may include software forperforming one or more computing tasks, as well as a trained system,such as a neural network (e.g., a trained deep neural network), or adeep neural network. For example, memory 4302 may include an analysismodule accessible by processor 4301 for receiving images and generatingoutput relative to one of the images, as described elsewhere in thisdisclosure.

In some embodiments, the analysis module may include at least onetrained model trained based on training data including a combination ofa plurality of images captured by cameras with at least partiallyoverlapping fields and LIDAR point cloud information corresponding withat least some of the plurality of images. For example, each of thetraining data sets may include three images, each of which may becaptured by one of a group of cameras (including a center camera, a leftsurround camera, and a right surround camera) mounted on a trainingvehicle. The FOV of the center camera may at least partially overlapwith the FOV of the left surround camera and the FOV of the rightsurround camera. The training data set may also include point cloudinformation captured by a LIDAR system mounted on the same vehicle,which may provide measured depth information associated with the imagescaptured by the group of cameras. The point cloud information may betreated as the reference depth information (or true depth values) fortraining the neural network. The images in the training data set (and/orextracted image features) may be input into a preliminary (or untrained)neural network, which may generate an output including calculatedper-pixel depth information for at least one region of the center image.The calculated per-pixel depth information may be compared with thecorresponding depth information of the point cloud information todetermine whether the neural network has the model parameters or weightsmeeting or exceeding a predetermined accuracy level for generatingper-pixel depth information. For example, the training system fortraining the neural network may generate an accuracy score of the neuralnetwork based on the comparison of the calculated depth information andthe corresponding depth information in the point cloud information(included in training data sets). If the accuracy score equals orexceeds a threshold, the training process may stop, and the trainingsystem may save the trained neural network into a local storage deviceand/or transmit the trained neural network to one or more vehicles(e.g., vehicle 4300). On the other hand, if the accuracy score is belowthe threshold, the training system may adjust one or more parameters orweights of the neural network and repeat the training process usingtraining data sets until an accuracy score of the neural network equalto or exceeding the threshold is reached (and/or a predetermined numberof training cycles has been reached).

In some embodiments, when training a neural network, a combination ofscore functions (or losses) may be used, which may include a photometricloss providing a score for the depth information calculated by thenetwork based on the images of the training data set. For the properdepth, the difference in appearance between corresponding image patchesmay be minimized, which may provide guidance in image regions in whichthere exist texture features. Additionally, a sparser score function maybe computed using a projection of LIDAR point measurements collected bythe LIDAR system of the training vehicle. These points may be aggregatedon one or more static objects in the scene using the vehicle's computedego-motion. The projection may account for the time differences betweenthe moment at which the pixel intensity of the image in which the depthinformation is to be calculated by the neural network during thetraining process may be recorded, and the capture time of the LIDAR datamay also be recorded. Static objects may be determined based onmonocular image object detectors to minimize the false negative rate (atthe price of a large false positive rate). In some embodiments, theneural network may also be trained to predict a confidence score of thecalculated depth information by regressing the magnitude of its owngeometric error, which may be optimized at training time using theLIDAR's geometric labeling.

In some embodiments, vehicle 4300 may receive the analysis module from aserver via a network and store the analysis module in memory 4302 and/orstorage device 4303.

Storage device 4303 may be configured to store various data andinformation for one or more components of vehicle 4300. Storage device4303 may include one or more hard drives, tapes, one or more solid-statedrives, any device suitable for writing and read data, or the like, or acombination thereof. For example, storage device 4303 may be configuredto store data of one or more maps. By way of example, storage device4303 may store data of a sparse map, which may include one or morelandmarks associated with a road segment and one or more targettrajectories associated with the road segment. As another example,storage device 4303 may be configured to store images captured by camera4306 and/or LIDAR data captured by LIDAR system 4307.

Communications port 4304 may be configured to facilitate datacommunications between vehicle 4300 and other devices. For example,communications port 4304 may be configured to receive data from andtransmit data to a server (e.g., one or more servers described in thisdisclosure) via one or more public or private networks, including theInternet, an Intranet, a WAN (Wide-Area Network), a MAN(Metropolitan-Area Network), a wireless network compliant with the IEEE802.11a/b/g/n Standards, a leased line, or the like.

I/O device 4305 may be configured to receive input from the user ofvehicle 4300, and one or more components of vehicle 4300 may perform oneor more functions in response to the input received. In someembodiments, I/O device 4305 may include an interface displayed on atouchscreen. I/O device 4305 may also be configured to outputinformation and/or data to the user. For example, I/O device 4305 mayinclude a display configured to display a map.

Cameras 4306 may be configured to capture one or more images of theenvironment of vehicle 4300. Cameras 4306 may include any type of devicesuitable for capturing at least one image from an environment. In someembodiments, cameras 4306 may be similar to image capture devices 122,124, and 126 illustrated in FIG. 1 and described above. For purposes ofbrevity, detailed descriptions are not repeated here.

Cameras 4306 may be positioned at any suitable location on vehicle 4300.For example, a camera 4306 may be located behind a windshield of vehicle4300, in a vicinity of a front bumper of vehicle 4300, a vicinity of therearview mirror of vehicle 4300, one or both of the side mirrors ofvehicle 4300, on the roof of vehicle 4300, on the hood of vehicle 4300,on the trunk of vehicle 4300, on the sides of vehicle 4300, mounted on,positioned behind, or positioned in front of any of the windows ofvehicle 4300, and mounted in or near light figures on the front and/orback of vehicle 4300, etc.

In some embodiments, cameras 4306 may include one or more groups ofcameras. Each group of cameras may include three cameras, namely acenter camera, a left surround camera, and a right surround camera. Byway of example, as illustrated in FIG. 44 , vehicle 4300 may include agroup of cameras, including a center camera 4410, a left surround camera4420, and a right surround camera 4430. Center camera 4410 may bepositioned in the vicinity of the rearview mirror and/or near the driverof vehicle 4300. Left surround camera 4420 and right surround camera4430 may be positioned on or in a bumper region of vehicle 4300. Otherconfigurations are also possible. For example, center camera 4410, leftsurround camera 4420, and right surround camera 4430 may be positionedin the vicinity of the rearview mirror and/or near the driver seat ofvehicle 4300.

In some embodiments, the FOV of center camera 4410 may at leastpartially overlap with both the FOV of left surround camera 4420 and aFOV of right surround camera 4430. By way of example, as illustrated inFIG. 44 , center camera 4410 may have a center camera FOV 4411, leftsurround camera 4420 may have a left surround FOV 4421, and rightsurround camera 4430 may have a right surround FOV 4431. Center cameraFOV 4411 may at least partially overlap with left surround FOV 4421 andright surround FOV 4431. For example, there may be an overlapping region4412 of center camera FOV 4411 and left surround FOV 4421, and anoverlapping region 4413 of center camera FOV 4411 and right surround FOV4431. In some embodiments, two or more of center camera 4410, leftsurround camera 4420, and right surround camera 4430 may have differentFOVs (as illustrated in FIG. 44 ).

In some embodiments, two or more of center camera 4410, left surroundcamera 4420, and right surround camera 4430 may have different focallengths. In some embodiments, the focal lengths of center camera 4410,left surround camera 4420, and right surround camera 4430 may beselected with a wide range of angular overlap between adjacent FOVs suchthat the system can infer depth information from the images captured bycenter camera 4410, left surround camera 4420, and right surround camera4430.

In some embodiments, vehicle 4300 may include two or more groups ofcameras. For example, vehicle 4300 may include a first group of cameras,including center camera 4410, left surround camera 4420, and rightsurround camera 4430. Vehicle 4300 may also include a second group ofcameras, including a center camera located in a vicinity of the rearviewmirror of vehicle 4300, a left surround camera located at the left, backside of vehicle 4300, and a right surround camera located at the right,back side of vehicle 4300. In some embodiments, the FOVs of the (two ormore) groups of cameras may form a total FOV covering 360 degrees.

In some embodiments, the groups of cameras may share at least onecamera. For example, instead of having another center camera in theexample provided above, the second group of cameras may include centercamera 4410 (of the first group) as the center camera of the secondgroup of cameras. As another example, vehicle 4300 may include three ormore groups of cameras, and the right surround camera of the firstcamera group may serve as the left surround camera of the second cameragroup and the left surround camera of the first camera group may serveras a right surround camera of a third camera group. Alternatively oradditionally, at least one of the left surround camera or the rightsurround camera of the first camera group may serve as a center camerafor a camera group other than the first camera group. One skilled in theart will understand that the above examples of the configurations of thecameras are for illustration purposes only and they are not intended tolimit the scope of the disclosure; other configurations of camerasand/or camera groups may also be used for implementing the disclosedsystems and methods.

LIDAR system 4307 may include one or more LIDAR units. In someembodiments, the one or more LIDAR units may be positioned on a roof ofvehicle 4300. Such a unit may include a rotating unit configured togather LIDAR reflection information within a 360-degree field of viewaround vehicle 4300 or from any sub-segment of the 360-degree field ofview (e.g., one or more FOVs each representing less than 360 degrees).The data collected by LIDAR system 4307 may be provided to processor4301. Alternatively or additionally, the data may be transmitted to aserver described in this disclosure via a network.

In some embodiments, a LIDAR unit may be positioned at a forwardlocation on vehicle 4300 (e.g., near the headlights, in the front grill,near the fog lamps, in a forward bumper, or at any other suitablelocation). In some cases, one or more LIDAR units installed on a forwardportion of vehicle 4300 may collect reflection information from a fieldof view in an environment forward of vehicle 4300. In other embodiments,a LIDAR unit may be located in other locations. For example, a LIDARunit may be located behind a windshield of vehicle 4300, in a vicinityof a front bumper of vehicle 4300, a vicinity of the rearview mirror ofvehicle 4300, one or both of the side mirrors of vehicle 4300, on theroof of vehicle 4300, on the hood of vehicle 4300, on the trunk ofvehicle 4300, on the sides of vehicle 4300, mounted on, positionedbehind, or positioned in front of any of the windows of vehicle 4300,and mounted in or near light figures on the front and/or back of vehicle4300, etc. By way of example, LIDAR system 4307 may be located on theroof of vehicle 4300, as illustrated in FIG. 44 .

Any suitable type of LIDAR unit may be included in vehicle 4300. In somecases, LIDAR system 4307 may include one or more flash (also referred toherein as static) LIDAR units (e.g., 3D flash LIDAR) where an entireLIDAR field of view (FOV) is illuminated with a single laser pulse, anda sensor including rows and columns of pixels to record returned lightintensity and time of flight/depth information. Such flash systems mayilluminate a scene and collect LIDAR “images” multiple times per second.Scanning LIDAR units may also be employed. Such scanning LIDAR units mayrely on one or more techniques for dispersing a laser beam over aparticular FOV. In some cases, a scanning LIDAR unit may include ascanning mirror that deflects and directs a laser beam toward objectswithin the FOV Scanning mirrors may rotate through a full 360 degrees ormay rotate along a single axis or multiple axes over less than 360degrees to direct the laser toward a predetermined FOV. In some cases,LIDAR units may scan one horizontal line. In other cases, a LIDAR unitmay scan multiple horizontal lines within an FOV, effectively rasteringa particular FOV multiple times per second.

The LIDAR units in LIDAR system 4307 may include any suitable lasersource. In some embodiments, the LIDAR units may employ a continuouslaser. In other cases, the LIDAR units may use pulsed laser emissions.Additionally, any suitable laser wavelength may be employed. In somecases, a wavelength of between about 600 nm to about 1000 nm may beused.

The LIDAR unit(s) in LIDAR system 4307 may also include any suitabletype of sensor and provide any suitable type of output. In some cases,sensors of the LIDAR units may include solid state photodetectors, suchas one or more photodiodes or photomultipliers. The sensors may alsoinclude one or more CMOS or CCD devices including any number of pixels.These sensors may be sensitive to laser light reflected from a scenewithin the LIDAR FOV. The sensors may enable various types of outputfrom a LIDAR unit. In some cases, a LIDAR unit may output raw lightintensity values and time of flight information representative of thereflected laser light collected at each sensor or at each pixel orsub-component of a particular sensor. Additionally or alternatively, aLIDAR unit may output a point cloud (e.g., a 3D point cloud) that mayinclude light intensity and depth/distance information relative to eachcollected point). LIDAR units may also output various types of depthmaps representative of light reflection amplitude and distance to pointswithin a field of view. LIDAR units may provide depth or distanceinformation relative to particular points within an FOV by noting a timeat which light from the LIDAR's light source was initially projectedtoward the FOV and recording a time at which the incident laser light isreceived by a sensor in the LIDAR unit. The time difference mayrepresent a time of flight, which may be directly related to the roundtrip distance that the incident laser light traveled from the lasersource to a reflecting object and back to the LIDAR unit. Monitoring thetime of flight information associated with individual laser spots orsmall segments of a LIDAR FOV may provide accurate distance informationfor a plurality of points within the FOV (e.g., mapping to even verysmall features of objects within the FOV). In some cases, LIDAR unitsmay output more complex information, such as classification informationthat correlates one or more laser reflections with a type of object fromwhich the laser reflection was acquired.

Navigation system 4308 may be configured to assist a driver of vehicle4300 to operate vehicle 4300. For example, navigation system 4308 maydetermine that vehicle 4300 is currently deviating from a targettrajectory and generate a notification to the driver indicating thedeviation from the target trajectory, which may be displayed on adisplay (e.g., displaying the target trajectory and an estimated travelpath determined based on vehicle 4300's current position and headingdirection). Alternatively, navigation system 4308 may include anautonomous vehicle navigation system configured to control the movementof vehicle 4300, as described elsewhere in this disclosure. For example,navigation system 4308 may implement a navigation action determined byprocessor 4301 as vehicle 4300 traverses a road segment (e.g., one ormore of steering, braking, or acceleration of the vehicle). In someembodiments, navigation system 4308 may include an advanceddriver-assistance system (ADAS) system. In some embodiments, navigationsystem 4308 may be configured to cause activation of one or moreactuators associated with a steering system, a braking system, or adrive system of vehicle 4300 according to one or more navigationalactions.

In some embodiments, vehicle 4300 may also include one or more sensorsconfigured to collect information relating to vehicle 4300 and/or theenvironment of vehicle 4300. Exemplary sensors may include a positioningdevice (e.g., a Global Positioning System (GPS) device), anaccelerometer, a gyro sensor, a speedometer, or the like, or acombination thereof. For example, vehicle 4300 may include a GPS deviceconfigured to collect positioning data associated with positions ofvehicle 4300 over a period of time.

FIG. 45 is a flowchart showing an exemplary process 4500 for determininga navigational action for a host vehicle consistent with disclosedembodiments. While some of the descriptions of process 4500 below areprovided with reference to center camera 4410, left surround camera4420, and right surround camera 4430 illustrated in FIG. 44 , oneskilled in the art will understand that one or more of cameras 4306 maybe located in other locations of vehicle 4300.

At step 4501, processor 4301 may be programmed to receive from centercamera 4410 at least one captured center image, which may include arepresentation of at least a portion of an environment of vehicle 4300.Processor 4301 may also be configured to receive from left surroundcamera 4420 at least one captured left surround image, which may includea representation of at least a portion of the environment of vehicle4300. Processor 4301 may further be configured to receive from rightsurround camera 4430 at least one captured right surround image, whichmay include a representation of at least a portion of the environment ofvehicle 4300. In some embodiments, the FOV of center camera 4410 may atleast partially overlap with both the FOV of left surround camera 4420and a FOV of right surround camera 4430. By way of example, asillustrated in FIG. 44 , center camera 4410 may include a center cameraFOV 4411, left surround camera 4420 may include a left surround FOV4421, and right surround camera 4430 may include a right surround FOV4431. Center camera FOV 4411 may at least partially overlap with leftsurround FOV 4421 and right surround FOV 4431. For example, there may bean overlapping region 4412 of center camera FOV 4411 and left surroundFOV 4421, and an overlapping region 4413 of center camera FOV 4411 andright surround FOV 4431.

Referring to FIG. 45 , at step 4502, processor 4301 may be programmed toprovide the at least one captured center image, the at least onecaptured left surround image, and the at least one captured rightsurround image to an analysis module configured to generate an outputrelative to the at least one captured center image based on analysis ofthe at least one captured center image, the at least one captured leftsurround image, and the at least one captured right surround image. Thegenerated output may include per-pixel depth information for at leastone region of the captured center image.

In some embodiments, the analysis module may include at least onetrained model. The trained model may include a trained neural network,which may be trained based on training data including a combination of aplurality of images captured by cameras with at least partiallyoverlapping fields and LIDAR point cloud information corresponding withat least some of the plurality of images. For example, each of thetraining data sets may include three images, each of which may becaptured by one of a group of cameras (including a center camera, a leftsurround camera, and a right surround camera) mounted on a trainingvehicle. The FOV of the center camera may at least partially overlapwith the FOV of the left surround camera and the FOV of the rightsurround camera. The training data set may also include point cloudinformation captured by a LIDAR system mounted on the same vehicle,which may provide measured depth information associated with the imagescaptured by the group of cameras. The point cloud information may betreated as the reference depth information (or true depth values) fortraining the neural network. The images in the training data set (and/orextracted image features) may be input into a preliminary (or untrained)neural network, which may generate an output including calculatedper-pixel depth information for at least one region of the center image.The calculated per-pixel depth information may be compared with thecorresponding depth information of the point cloud information todetermine whether the neural network has the model parameters or weightsmeeting or exceeding a predetermined accuracy level for generatingper-pixel depth information. For example, the training system fortraining the neural network may generate an accuracy score of the neuralnetwork based on the comparison of the calculated depth information andthe corresponding depth information in the point cloud information(included in training data sets). If the accuracy score equals orexceeds a threshold, the training process may stop, and the trainingsystem may save the trained neural network into a local storage deviceand/or transmit the trained neural network to one or more vehicles(e.g., vehicle 4300). On the other hand, if the accuracy score is belowthe threshold, the training system may adjust one or more parameters orweights of the neural network and repeat the training process usingtraining data sets until an accuracy score of the neural network equalto or exceeding the threshold is reached (and/or a predetermined numberof training cycles has been reached).

In some embodiments, before providing the images to the analysis module,processor 4301 may generate a set of synthetic pinhole images sharingthe orientations of the image axes and the direction of the images'principal axes, based on the images and the parameters of the cameras(e.g., the orientations of their image axes and the direction of theirprincipal axis). This preprocess step may allow for an efficient warp(homogeneous image scale-translate). Processor 4301 may also input thegenerated synthetic pinhole images (rather than the original images)into the analysis module to generate an output.

In some embodiments, processor 4301 may input the images into theanalysis module, which may be run by processor 4301. The analysis modulemay generate an output including per-pixel depth information for atleast one region of the captured center image.

In some embodiments, vehicle 4300 may receive the analysis module from aserver via a network and store the analysis module in memory 4302 and/orstorage device 4303.

In some embodiments, the generated output by the analysis module mayinclude per-pixel depth information for at least one region (or allregions) of the captured center image. In some embodiments, theper-pixel depth information for the at least one region of the capturedcenter image may provide or include depth information for one or moreobjects represented in the captured center image. In some cases, the oneor more objects may not contact a ground surface (e.g., a road surface).For monocular systems, a ground plane may be needed to obtain the depthinformation through a process such as structure in motion, which may notbe needed in the disclosed systems herein. In some embodiments, the oneor more objects may be associated with a target vehicle (or beingcarried by the target vehicle).

In some embodiments, the per-pixel depth information for the at leastone region of the captured center image may provide or include depthinformation for a surface of at least one object represented in thecaptured center image, and the surface of the at least one object mayinclude a reflection of one or more other objects, as the analysismodule may recognize surfaces based at least in part on edges of thesurfaces and can recognize that reflections are on the surface and notindicative of a farther object beyond the surface.

In some embodiments, the per-pixel depth information for the at leastone region of the captured center image may provide or include depthinformation relative to an object that is at least partially obscuredfrom view in one or more of the at least one captured center image, theat least one captured left surround image, or the at least one capturedright surround image, as the analysis module may provide depthinformation even where an object is partially occluded from view in oneor more of the captured images.

In some embodiments, as described above, vehicle 4300 may include two ormore groups of cameras. For example, vehicle 4300 may include a firstgroup of cameras, including center camera 4410, left surround camera4420, and right surround camera 4430. Vehicle 4300 may also include asecond group of cameras, including a center camera located in a vicinityof the rearview mirror of vehicle 4300, a left surround camera locatedat the left, back side of vehicle 4300, and a right surround cameralocated at the right, back side of vehicle 4300. The analysis module maybe further configured to generate another output relative to at leastone center image captured by the center camera of the second cameragroup, based on analysis of at least one captured center image, at leastone captured left surround image, and at least one captured rightsurround image received from the cameras of the second camera group, andthe another generated output may include per-pixel depth information forat least one region of the center image captured by the center camera ofthe second camera group. In some embodiments, the analysis module may beconfigured to generate per pixel depth information for at least oneimage captured by at least one camera in each of the first camera groupand the at least a second camera group, to provide a 360-degreeimage-generated point cloud surrounding vehicle.

At step 4503, processor 4301 may be programmed to cause at least onenavigational action by vehicle 4300 based on the generated outputincluding the per-pixel depth information for the at least one region ofthe captured center image. For example, processor 4301 may analyze thegenerated output including the per-pixel depth information for the atleast one region of the captured center image and detect one or moreobjects based on the generated output. Processor 4301 may also beconfigured to determine at least one navigational action by vehicle 4300based on the detected object(s), as described elsewhere in thisdisclosure. Processor 4301 may further be configured to cause vehicle4300 to implement the determined navigational action, as describedelsewhere in this disclosure. For example, processor 4301 may determineat least one of maintaining a current heading direction and speed forvehicle 4300, changing a current heading direction for vehicle 4300(e.g., turning vehicle 4300), or changing a speed of vehicle 4300 (e.g.,accelerating or braking vehicle 4300). By way of example, processor 4301may analyze the generated output and identify an object that is within apredetermined safety distance based on the analysis of the generatedoutput. Processor 4301 may also be configured to determine anavigational action for vehicle 4300 to slow vehicle 4300 or steer awayfrom the identified object. Processor 4301 may further be configured tocontrol navigation system 4308 to cause activation of one or moreactuators associated with a steering system, a braking system, or adrive system of vehicle 4300 according to one or more navigationalactions.

In some embodiments, processor 4301 may be configured to determine theat least one navigational action based on a combination of the per-pixeldepth information for the at least one region of the captured centerimage and point cloud information received from LIDAR system 4307. Insome embodiments, processor 4301 may average the depth values associatedwith an object appearing in both the per-pixel depth information for theat least one region of the captured center image and corresponding pointcloud information received from LIDAR system 4307 to obtain averageddepths values associated with the object. Processor 4301 may alsodetermine a navigational action based on the averaged depths associatedwith the object (e.g., maintaining the current speed and the headingdirection). Alternatively or additionally, processor 4301 may applydifferent weights to the depth values obtained from the per-pixel depthinformation for the at least one region of the captured center image andthe depth values obtained from point cloud information received fromLIDAR system 4307 (which may be similar to a process described inconnection with step 4104 above). Processor 4301 may also be configuredto determine at least one navigational action based on weighted depthvalues. For example, as described above, a LIDAR system may performbetter in a sun glare environment (or a highly reflective environment,or a low light condition during night time without street lights, etc.)than cameras. In a sun glare environment (or a highly reflectiveenvironment, or a low light condition during night time without streetlights, etc.), processor 4301 may apply a higher weight to the depthvalues obtained based on the point cloud information received from LIDARsystem 4307 than the weight applied to the depth values obtained fromthe per-pixel depth information for the at least one region of thecaptured center image. On the other hand, cameras may perform better ona foggy or rainy day than a LIDAR system, and in such an environment,processor 4301 apply a lower weight to the depth values obtained basedon the point cloud information received from LIDAR system 4307 than theweight applied to the depth values obtained from the per-pixel depthinformation for the at least one region of the captured center image.

The foregoing description has been presented for purposes ofillustration. It is not exhaustive and is not limited to the preciseforms or embodiments disclosed. Modifications and adaptations will beapparent to those skilled in the art from consideration of thespecification and practice of the disclosed embodiments. Additionally,although aspects of the disclosed embodiments are described as beingstored in memory, one skilled in the art will appreciate that theseaspects can also be stored on other types of computer-readable media,such as secondary storage devices, for example, hard disks or CD ROM, orother forms of RAM or ROM, USB media, DVD, Blu-ray, 4K Ultra HD Blu-ray,or other optical drive media.

Computer programs based on the written description and disclosed methodsare within the skill of an experienced developer. The various programsor program modules can be created using any of the techniques known toone skilled in the art or can be designed in connection with existingsoftware. For example, program sections or program modules can bedesigned in or by means of .Net Framework, .Net Compact Framework (andrelated languages, such as Visual Basic, C, etc.), Java, C++,Objective-C, HTML, HTML/AJAX combinations, XML, or HTML with includedJava applets.

Moreover, while illustrative embodiments have been described herein, thescope of any and all embodiments having equivalent elements,modifications, omissions, combinations (e.g., of aspects across variousembodiments), adaptations and/or alterations as would be appreciated bythose skilled in the art based on the present disclosure. Thelimitations in the claims are to be interpreted broadly based on thelanguage employed in the claims and not limited to examples described inthe present specification or during the prosecution of the application.The examples are to be construed as non-exclusive. Furthermore, thesteps of the disclosed methods may be modified in any manner, includingby reordering steps and/or inserting or deleting steps. It is intended,therefore, that the specification and examples be considered asillustrative only, with a true scope and spirit being indicated by thefollowing claims and their full scope of equivalents.

What is claimed is:
 1. A navigation system for a host vehicle, thenavigation system comprising: at least one processor programmed to:receive, from an entity remotely located relative to the host vehicle, asparse map associated with at least one road segment to be traversed bythe host vehicle, wherein the sparse map includes a plurality of mappednavigational landmarks and at least one target trajectory, wherein boththe plurality of mapped navigational landmarks and the at least onetarget trajectory were generated based on drive information collectedfrom a plurality of vehicles that traveled previously along the at leastone road segment; receive point cloud information from a LIDAR systemonboard the host vehicle, the point cloud information beingrepresentative of distances to various objects in an environment of thehost vehicle; compare the received point cloud information with at leastone of the plurality of mapped navigational landmarks in the sparse mapto provide a LIDAR-based localization of the host vehicle relative tothe at least one target trajectory; determine at least one navigationalaction for the host vehicle based on the LIDAR-based localization of thehost vehicle relative to the at least one target trajectory; and causethe at least one navigational action to be taken by the host vehicle. 2.The navigation system of claim 1, wherein the LIDAR-based localizationof the host vehicle relative to the at least one target trajectoryincludes determining a current position of the host vehicle relative tothe at least one target trajectory.
 3. The navigation system of claim 1,wherein the at least one navigational action includes maintaining acurrent heading direction for the host vehicle.
 4. The navigation systemof claim 1, wherein the at least one navigational action includeschanging a current heading direction for the host vehicle to reduce adistance between the host vehicle and the at least one targettrajectory.
 5. The navigation system of claim 1, wherein the LIDAR-basedlocalization of the host vehicle relative to the at least one targettrajectory includes: identifying representations in the point cloudinformation of at least two of the plurality of mapped navigationallandmarks; determining, based on the point cloud information, relativedistances between a reference point associated with the host vehicle andeach of the at least two of the plurality of mapped navigationallandmarks; and determining a current position of the host vehiclerelative to the at least one target trajectory based on the relativedistances between the reference point associated with the host vehicleand each of the at least two of the plurality of mapped navigationallandmarks.
 6. The navigation system of claim 5, wherein the referencepoint associated with the host vehicle is located on the LIDAR systemonboard the host vehicle.
 7. The navigation system of claim 5, whereinthe reference point associated with the host vehicle is located on acamera onboard the host vehicle.
 8. The navigation system of claim 5,wherein the identifying of representations in the point cloudinformation of the at least two of the plurality of mapped navigationallandmarks is performed by a trained neural network.
 9. The navigationsystem of claim 1, wherein the point cloud information includes at leasta first LIDAR scan point cloud and a second LIDAR scan point cloud, andwherein the LIDAR-based localization of the host vehicle relative to theat least one target trajectory includes: identifying a representation inthe first LIDAR scan point cloud of at least one of the plurality ofmapped navigational landmarks; determining, based on first LIDAR scanpoint cloud, a first relative distance between a reference pointassociated with the host vehicle and the at least one of the pluralityof mapped navigational landmarks; identifying a representation in thesecond LIDAR scan point cloud of the at least one of the plurality ofmapped navigational landmarks; determining, based on first second scanpoint cloud, a second relative distance between the reference pointassociated with the host vehicle and the at least one of the pluralityof mapped navigational landmarks; and determining a current position ofthe host vehicle relative to the at least one target trajectory based onthe first and second relative distances.
 10. The navigation system ofclaim 9, wherein the LIDAR-based localization of the host vehiclerelative to the at least one target trajectory may further includeaccounting for ego motion of the host vehicle between a first timeassociated with acquisition of the first LIDAR scan point cloud and asecond time associated with acquisition of the second LIDAR scan pointcloud.
 11. The navigation system of claim 9, wherein the identifying ofa representation in the first LIDAR scan point cloud of at least one ofthe plurality of mapped navigational landmarks and the identifying of arepresentation in the second LIDAR scan point cloud of the at least oneof the plurality of mapped navigational landmarks is performed by atrained neural network.
 12. The navigation system of claim 1, whereinthe LIDAR-based localization of the host vehicle relative to the atleast one target trajectory includes: identifying a representation inthe point cloud information of at least one of the plurality of mappednavigational landmarks; comparing one or more aspects of the at leastone of the plurality of mapped navigational landmarks represented in thepoint cloud information to an expected set of characteristics for the atleast one of the plurality of mapped navigational landmarks determinedbased on the sparse map; and determining a current position of the hostvehicle relative to the at least one target trajectory based on thecomparison.
 13. The navigation system of claim 12, wherein the set ofcharacteristics include at least one of a size or a two-dimensionallocation within a LIDAR scan frame of the representation of the at leastone of the plurality of mapped navigational landmarks in the point cloudinformation.
 14. The navigation system of claim 12, wherein the one ormore aspects of the at least one of the plurality of mapped navigationallandmarks include at least one of a size or a two-dimensional locationwithin a LIDAR scan frame of the representation of the at least one ofthe plurality of mapped navigational landmarks in the point cloudinformation.
 15. The navigation system of claim 12, wherein theidentifying of a representation in the point cloud information of the atleast one of the plurality of mapped navigational landmarks is performedby a trained neural network.
 16. The navigation system of claim 1,wherein the point cloud information is limited to point cloud depthinformation associated with one or more vertically oriented objects inthe environment of the host vehicle.
 17. The navigation system of claim16, wherein the vertically oriented objects include at least one of asign post, a lamp post, road divider stanchion, guard rail support, ortree trunk.
 18. The navigation system of claim 1, wherein the at leastone target trajectory is represented in the sparse map by athree-dimensional spline.
 19. The navigation system of claim 1, whereinat least some of the plurality of mapped navigational landmarks arerepresented in the sparse map by a point location and an object typeclassification.
 20. The navigation system of claim 1, wherein at leastsome of the plurality of mapped navigational landmarks are representedin the sparse map by multiple point locations and one or more objectdescriptors.
 21. The navigation system of claim 1, wherein the at leastone processor is further programmed to: receive, from a camera onboardthe host vehicle, at least one captured image including a representationof at least a portion of an environment of the host vehicle; identifyrepresentations in the at least one captured image of the plurality ofmapped navigational landmarks; and localize the host vehicle relative tothe at least one target trajectory based on the sparse map and based onthe representations in the at least one captured image of the pluralityof mapped navigational landmarks to provide an image-based localization.22. The navigation system of claim 21, wherein the determination of theat least one navigational action for the host vehicle is based on acombination of the LIDAR-based localization and the image-basedlocalization.
 23. The navigation system of claim 21, wherein theprocessor is further programmed to determine a difference associatedwith the LIDAR-based localization and the image-based localization. 24.The navigation system of claim 23, wherein the at least one processor isfurther programmed to implement at least one remedial action if thedifference exceeds a predetermined threshold.
 25. The navigation systemof claim 24, wherein the remedial action includes at least one of:slowing the host vehicle, stopping the host vehicle, or issuing awarning of a system irregularity.
 26. The navigation system of claim 23,wherein the at least one processor is further programmed to applyweights to the each of the LIDAR-based localization and the image-basedlocalization.
 27. The navigation system of claim 26, wherein the weightsare determined based on an environmental condition detected in theenvironment of the host vehicle.
 28. A method for controlling anavigation system for a host vehicle, the method comprising: receiving,from an entity remotely located relative to the host vehicle, a sparsemap associated with at least one road segment to be traversed by thehost vehicle, wherein the sparse map includes a plurality of mappednavigational landmarks and at least one target trajectory, wherein boththe plurality of mapped navigational landmarks and the at least onetarget trajectory were generated based on drive information collectedfrom a plurality of vehicles that traveled previously along the at leastone road segment; receiving point cloud information from a LIDAR systemonboard the host vehicle, the point cloud information beingrepresentative of distances to various objects in an environment of thehost vehicle; comparing the received point cloud information with atleast one of the plurality of mapped navigational landmarks in thesparse map to provide a LIDAR-based localization of the host vehiclerelative to the at least one target trajectory; determining at least onenavigational action for the host vehicle based on the LIDAR-basedlocalization of the host vehicle relative to the at least one targettrajectory; and causing the at least one navigational action to be takenby the host vehicle.
 29. A computer-readable medium storing instructionsthat when executed by at least one processor, are configured to causeprocessor 3401 programmed to: receive, from an entity remotely locatedrelative to a host vehicle, a sparse map associated with at least oneroad segment to be traversed by the host vehicle, wherein the sparse mapincludes a plurality of mapped navigational landmarks and at least onetarget trajectory, wherein both the plurality of mapped navigationallandmarks and the at least one target trajectory were generated based ondrive information collected from a plurality of vehicles that traveledpreviously along the at least one road segment; receive point cloudinformation from a LIDAR system onboard the host vehicle, the pointcloud information being representative of distances to various objectsin an environment of the host vehicle; compare the received point cloudinformation with at least one of the plurality of mapped navigationallandmarks in the sparse map to provide a LIDAR-based localization of thehost vehicle relative to the at least one target trajectory; determineat least one navigational action for the host vehicle based on theLIDAR-based localization of the host vehicle relative to the at leastone target trajectory; and cause the at least one navigational action tobe taken by the host vehicle.